| Index Entry |   |  Section | 
 
  | 
| # |  |  | 
 | #pragma: |   | Pragmas | 
 | #pragma implementation: |   | C++ Interface | 
 | #pragma implementation, implied: |   | C++ Interface | 
 | #pragma interface: |   | C++ Interface | 
 
  | 
| $ |  |  | 
 | $: |   | Dollar Signs | 
 
  | 
| % |  |  | 
 | ‘%’ in constraint: |   | Modifiers | 
 | %include: |   | Spec Files | 
 | %include_noerr: |   | Spec Files | 
 | %rename: |   | Spec Files | 
 
  | 
| & |  |  | 
 | ‘&’ in constraint: |   | Modifiers | 
 
  | 
| ' |  |  | 
 | ': |   | Incompatibilities | 
 
  | 
| * |  |  | 
 | *__builtin_alloca: |   | Other Builtins | 
 | *__builtin_alloca_with_align: |   | Other Builtins | 
 | *__builtin_alloca_with_align_and_max: |   | Other Builtins | 
 
  | 
| + |  |  | 
 | ‘+’ in constraint: |   | Modifiers | 
 
  | 
| - |  |  | 
 | -lgcc, use with -nodefaultlibs: |   | Link Options | 
 | -lgcc, use with -nostdlib: |   | Link Options | 
 | -march feature modifiers: |   | AArch64 Options | 
 | -mcpu feature modifiers: |   | AArch64 Options | 
 | -nodefaultlibs and unresolved references: |   | Link Options | 
 | -nostdlib and unresolved references: |   | Link Options | 
 
  | 
| . |  |  | 
 | .sdata/.sdata2 references (PowerPC): |   | RS/6000 and PowerPC Options | 
 
  | 
| / |  |  | 
 | //: |   | C++ Comments | 
 
  | 
| 0 |  |  | 
 | ‘0’ in constraint: |   | Simple Constraints | 
 
  | 
| < |  |  | 
 | ‘<’ in constraint: |   | Simple Constraints | 
 
  | 
| = |  |  | 
 | ‘=’ in constraint: |   | Modifiers | 
 
  | 
| > |  |  | 
 | ‘>’ in constraint: |   | Simple Constraints | 
 
  | 
| ? |  |  | 
 | ?: extensions: |   | Conditionals | 
 | ?: side effect: |   | Conditionals | 
 
  | 
| _ |  |  | 
 | ‘_’ in variables in macros: |   | Typeof | 
 | _Accum data type: |   | Fixed-Point | 
 | _Complex keyword: |   | Complex | 
 | _Decimal128 data type: |   | Decimal Float | 
 | _Decimal32 data type: |   | Decimal Float | 
 | _Decimal64 data type: |   | Decimal Float | 
 | _Exit: |   | Other Builtins | 
 | _exit: |   | Other Builtins | 
 | _Floatn data types: |   | Floating Types | 
 | _Floatnx data types: |   | Floating Types | 
 | _Fract data type: |   | Fixed-Point | 
 | _get_ssp: |   | x86 control-flow protection intrinsics | 
 | _HTM_FIRST_USER_ABORT_CODE: |   | S/390 System z Built-in Functions | 
 | _inc_ssp: |   | x86 control-flow protection intrinsics | 
 | _Sat data type: |   | Fixed-Point | 
 | _xabort: |   | x86 transactional memory intrinsics | 
 | _xbegin: |   | x86 transactional memory intrinsics | 
 | _xend: |   | x86 transactional memory intrinsics | 
 | _xtest: |   | x86 transactional memory intrinsics | 
 | __atomic_add_fetch: |   | __atomic Builtins | 
 | __atomic_always_lock_free: |   | __atomic Builtins | 
 | __atomic_and_fetch: |   | __atomic Builtins | 
 | __atomic_clear: |   | __atomic Builtins | 
 | __atomic_compare_exchange: |   | __atomic Builtins | 
 | __atomic_compare_exchange_n: |   | __atomic Builtins | 
 | __atomic_exchange: |   | __atomic Builtins | 
 | __atomic_exchange_n: |   | __atomic Builtins | 
 | __atomic_fetch_add: |   | __atomic Builtins | 
 | __atomic_fetch_and: |   | __atomic Builtins | 
 | __atomic_fetch_nand: |   | __atomic Builtins | 
 | __atomic_fetch_or: |   | __atomic Builtins | 
 | __atomic_fetch_sub: |   | __atomic Builtins | 
 | __atomic_fetch_xor: |   | __atomic Builtins | 
 | __atomic_is_lock_free: |   | __atomic Builtins | 
 | __atomic_load: |   | __atomic Builtins | 
 | __atomic_load_n: |   | __atomic Builtins | 
 | __atomic_nand_fetch: |   | __atomic Builtins | 
 | __atomic_or_fetch: |   | __atomic Builtins | 
 | __atomic_signal_fence: |   | __atomic Builtins | 
 | __atomic_store: |   | __atomic Builtins | 
 | __atomic_store_n: |   | __atomic Builtins | 
 | __atomic_sub_fetch: |   | __atomic Builtins | 
 | __atomic_test_and_set: |   | __atomic Builtins | 
 | __atomic_thread_fence: |   | __atomic Builtins | 
 | __atomic_xor_fetch: |   | __atomic Builtins | 
 | __builtin_addf128_round_to_odd: |   | Basic PowerPC Built-in Functions Available on ISA 3.0 | 
 | __builtin_add_overflow: |   | Integer Overflow Builtins | 
 | __builtin_add_overflow_p: |   | Integer Overflow Builtins | 
 | __builtin_alloca: |   | Other Builtins | 
 | __builtin_alloca_with_align: |   | Other Builtins | 
 | __builtin_alloca_with_align_and_max: |   | Other Builtins | 
 | __builtin_apply: |   | Constructing Calls | 
 | __builtin_apply_args: |   | Constructing Calls | 
 | __builtin_arc_aligned: |   | ARC Built-in Functions | 
 | __builtin_arc_brk: |   | ARC Built-in Functions | 
 | __builtin_arc_core_read: |   | ARC Built-in Functions | 
 | __builtin_arc_core_write: |   | ARC Built-in Functions | 
 | __builtin_arc_divaw: |   | ARC Built-in Functions | 
 | __builtin_arc_flag: |   | ARC Built-in Functions | 
 | __builtin_arc_lr: |   | ARC Built-in Functions | 
 | __builtin_arc_mul64: |   | ARC Built-in Functions | 
 | __builtin_arc_mulu64: |   | ARC Built-in Functions | 
 | __builtin_arc_nop: |   | ARC Built-in Functions | 
 | __builtin_arc_norm: |   | ARC Built-in Functions | 
 | __builtin_arc_normw: |   | ARC Built-in Functions | 
 | __builtin_arc_rtie: |   | ARC Built-in Functions | 
 | __builtin_arc_sleep: |   | ARC Built-in Functions | 
 | __builtin_arc_sr: |   | ARC Built-in Functions | 
 | __builtin_arc_swap: |   | ARC Built-in Functions | 
 | __builtin_arc_swi: |   | ARC Built-in Functions | 
 | __builtin_arc_sync: |   | ARC Built-in Functions | 
 | __builtin_arc_trap_s: |   | ARC Built-in Functions | 
 | __builtin_arc_unimp_s: |   | ARC Built-in Functions | 
 | __builtin_assume_aligned: |   | Other Builtins | 
 | __builtin_bswap16: |   | Other Builtins | 
 | __builtin_bswap32: |   | Other Builtins | 
 | __builtin_bswap64: |   | Other Builtins | 
 | __builtin_call_with_static_chain: |   | Other Builtins | 
 | __builtin_call_with_static_chain: |   | Other Builtins | 
 | __builtin_choose_expr: |   | Other Builtins | 
 | __builtin_clrsb: |   | Other Builtins | 
 | __builtin_clrsbl: |   | Other Builtins | 
 | __builtin_clrsbll: |   | Other Builtins | 
 | __builtin_clz: |   | Other Builtins | 
 | __builtin_clzl: |   | Other Builtins | 
 | __builtin_clzll: |   | Other Builtins | 
 | __builtin_complex: |   | Other Builtins | 
 | __builtin_constant_p: |   | Other Builtins | 
 | __builtin_convertvector: |   | Vector Extensions | 
 | __builtin_cpu_init: |   | Basic PowerPC Built-in Functions Available on all Configurations | 
 | __builtin_cpu_init: |   | x86 Built-in Functions | 
 | __builtin_cpu_is: |   | Basic PowerPC Built-in Functions Available on all Configurations | 
 | __builtin_cpu_is: |   | x86 Built-in Functions | 
 | __builtin_cpu_supports: |   | Basic PowerPC Built-in Functions Available on all Configurations | 
 | __builtin_cpu_supports: |   | x86 Built-in Functions | 
 | __builtin_ctz: |   | Other Builtins | 
 | __builtin_ctzl: |   | Other Builtins | 
 | __builtin_ctzll: |   | Other Builtins | 
 | __builtin_divf128_round_to_odd: |   | Basic PowerPC Built-in Functions Available on ISA 3.0 | 
 | __builtin_expect: |   | Other Builtins | 
 | __builtin_expect_with_probability: |   | Other Builtins | 
 | __builtin_extend_pointer: |   | Other Builtins | 
 | __builtin_extend_pointer: |   | Other Builtins | 
 | __builtin_extract_return_addr: |   | Return Address | 
 | __builtin_ffs: |   | Other Builtins | 
 | __builtin_ffsl: |   | Other Builtins | 
 | __builtin_ffsll: |   | Other Builtins | 
 | __builtin_FILE: |   | Other Builtins | 
 | __builtin_fmaf128_round_to_odd: |   | Basic PowerPC Built-in Functions Available on ISA 3.0 | 
 | __builtin_fpclassify: |   | Other Builtins | 
 | __builtin_fpclassify: |   | Other Builtins | 
 | __builtin_frame_address: |   | Return Address | 
 | __builtin_frob_return_address: |   | Return Address | 
 | __builtin_FUNCTION: |   | Other Builtins | 
 | __builtin_goacc_parlevel_id: |   | Other Builtins | 
 | __builtin_goacc_parlevel_size: |   | Other Builtins | 
 | __builtin_has_attribute: |   | Other Builtins | 
 | __builtin_has_attribute: |   | Other Builtins | 
 | __builtin_huge_val: |   | Other Builtins | 
 | __builtin_huge_valf: |   | Other Builtins | 
 | __builtin_huge_valfn: |   | Other Builtins | 
 | __builtin_huge_valfnx: |   | Other Builtins | 
 | __builtin_huge_vall: |   | Other Builtins | 
 | __builtin_huge_valq: |   | x86 Built-in Functions | 
 | __builtin_inf: |   | Other Builtins | 
 | __builtin_infd128: |   | Other Builtins | 
 | __builtin_infd32: |   | Other Builtins | 
 | __builtin_infd64: |   | Other Builtins | 
 | __builtin_inff: |   | Other Builtins | 
 | __builtin_inffn: |   | Other Builtins | 
 | __builtin_inffnx: |   | Other Builtins | 
 | __builtin_infl: |   | Other Builtins | 
 | __builtin_infq: |   | x86 Built-in Functions | 
 | __builtin_isfinite: |   | Other Builtins | 
 | __builtin_isgreater: |   | Other Builtins | 
 | __builtin_isgreaterequal: |   | Other Builtins | 
 | __builtin_isinf_sign: |   | Other Builtins | 
 | __builtin_isinf_sign: |   | Other Builtins | 
 | __builtin_isless: |   | Other Builtins | 
 | __builtin_islessequal: |   | Other Builtins | 
 | __builtin_islessgreater: |   | Other Builtins | 
 | __builtin_isnormal: |   | Other Builtins | 
 | __builtin_isunordered: |   | Other Builtins | 
 | __builtin_is_constant_evaluated: |   | Other Builtins | 
 | __builtin_LINE: |   | Other Builtins | 
 | __builtin_longjmp: |   | Nonlocal Gotos | 
 | __builtin_mulf128_round_to_odd: |   | Basic PowerPC Built-in Functions Available on ISA 3.0 | 
 | __builtin_mul_overflow: |   | Integer Overflow Builtins | 
 | __builtin_mul_overflow_p: |   | Integer Overflow Builtins | 
 | __builtin_nan: |   | Other Builtins | 
 | __builtin_nand128: |   | Other Builtins | 
 | __builtin_nand32: |   | Other Builtins | 
 | __builtin_nand64: |   | Other Builtins | 
 | __builtin_nanf: |   | Other Builtins | 
 | __builtin_nanfn: |   | Other Builtins | 
 | __builtin_nanfnx: |   | Other Builtins | 
 | __builtin_nanl: |   | Other Builtins | 
 | __builtin_nanq: |   | x86 Built-in Functions | 
 | __builtin_nans: |   | Other Builtins | 
 | __builtin_nansf: |   | Other Builtins | 
 | __builtin_nansfn: |   | Other Builtins | 
 | __builtin_nansfnx: |   | Other Builtins | 
 | __builtin_nansl: |   | Other Builtins | 
 | __builtin_nansq: |   | x86 Built-in Functions | 
 | __builtin_nds32_isb: |   | NDS32 Built-in Functions | 
 | __builtin_nds32_isync: |   | NDS32 Built-in Functions | 
 | __builtin_nds32_mfsr: |   | NDS32 Built-in Functions | 
 | __builtin_nds32_mfusr: |   | NDS32 Built-in Functions | 
 | __builtin_nds32_mtsr: |   | NDS32 Built-in Functions | 
 | __builtin_nds32_mtusr: |   | NDS32 Built-in Functions | 
 | __builtin_nds32_setgie_dis: |   | NDS32 Built-in Functions | 
 | __builtin_nds32_setgie_en: |   | NDS32 Built-in Functions | 
 | __builtin_non_tx_store: |   | S/390 System z Built-in Functions | 
 | __builtin_object_size: |   | Object Size Checking | 
 | __builtin_object_size: |   | Object Size Checking | 
 | __builtin_object_size: |   | Other Builtins | 
 | __builtin_object_size: |   | Other Builtins | 
 | __builtin_offsetof: |   | Offsetof | 
 | __builtin_parity: |   | Other Builtins | 
 | __builtin_parityl: |   | Other Builtins | 
 | __builtin_parityll: |   | Other Builtins | 
 | __builtin_popcount: |   | Other Builtins | 
 | __builtin_popcountl: |   | Other Builtins | 
 | __builtin_popcountll: |   | Other Builtins | 
 | __builtin_powi: |   | Other Builtins | 
 | __builtin_powi: |   | Other Builtins | 
 | __builtin_powif: |   | Other Builtins | 
 | __builtin_powif: |   | Other Builtins | 
 | __builtin_powil: |   | Other Builtins | 
 | __builtin_powil: |   | Other Builtins | 
 | __builtin_prefetch: |   | Other Builtins | 
 | __builtin_return: |   | Constructing Calls | 
 | __builtin_return_address: |   | Return Address | 
 | __builtin_rx_brk: |   | RX Built-in Functions | 
 | __builtin_rx_clrpsw: |   | RX Built-in Functions | 
 | __builtin_rx_int: |   | RX Built-in Functions | 
 | __builtin_rx_machi: |   | RX Built-in Functions | 
 | __builtin_rx_maclo: |   | RX Built-in Functions | 
 | __builtin_rx_mulhi: |   | RX Built-in Functions | 
 | __builtin_rx_mullo: |   | RX Built-in Functions | 
 | __builtin_rx_mvfachi: |   | RX Built-in Functions | 
 | __builtin_rx_mvfacmi: |   | RX Built-in Functions | 
 | __builtin_rx_mvfc: |   | RX Built-in Functions | 
 | __builtin_rx_mvtachi: |   | RX Built-in Functions | 
 | __builtin_rx_mvtaclo: |   | RX Built-in Functions | 
 | __builtin_rx_mvtc: |   | RX Built-in Functions | 
 | __builtin_rx_mvtipl: |   | RX Built-in Functions | 
 | __builtin_rx_racw: |   | RX Built-in Functions | 
 | __builtin_rx_revw: |   | RX Built-in Functions | 
 | __builtin_rx_rmpa: |   | RX Built-in Functions | 
 | __builtin_rx_round: |   | RX Built-in Functions | 
 | __builtin_rx_sat: |   | RX Built-in Functions | 
 | __builtin_rx_setpsw: |   | RX Built-in Functions | 
 | __builtin_rx_wait: |   | RX Built-in Functions | 
 | __builtin_saddll_overflow: |   | Integer Overflow Builtins | 
 | __builtin_saddl_overflow: |   | Integer Overflow Builtins | 
 | __builtin_sadd_overflow: |   | Integer Overflow Builtins | 
 | __builtin_setjmp: |   | Nonlocal Gotos | 
 | __builtin_set_thread_pointer: |   | SH Built-in Functions | 
 | __builtin_shuffle: |   | Vector Extensions | 
 | __builtin_sh_get_fpscr: |   | SH Built-in Functions | 
 | __builtin_sh_set_fpscr: |   | SH Built-in Functions | 
 | __builtin_smulll_overflow: |   | Integer Overflow Builtins | 
 | __builtin_smull_overflow: |   | Integer Overflow Builtins | 
 | __builtin_smul_overflow: |   | Integer Overflow Builtins | 
 | __builtin_speculation_safe_value: |   | Other Builtins | 
 | __builtin_speculation_safe_value: |   | Other Builtins | 
 | __builtin_sqrtf128_round_to_odd: |   | Basic PowerPC Built-in Functions Available on ISA 3.0 | 
 | __builtin_ssubll_overflow: |   | Integer Overflow Builtins | 
 | __builtin_ssubl_overflow: |   | Integer Overflow Builtins | 
 | __builtin_ssub_overflow: |   | Integer Overflow Builtins | 
 | __builtin_subf128_round_to_odd: |   | Basic PowerPC Built-in Functions Available on ISA 3.0 | 
 | __builtin_sub_overflow: |   | Integer Overflow Builtins | 
 | __builtin_sub_overflow_p: |   | Integer Overflow Builtins | 
 | __builtin_tabort: |   | S/390 System z Built-in Functions | 
 | __builtin_tbegin: |   | S/390 System z Built-in Functions | 
 | __builtin_tbeginc: |   | S/390 System z Built-in Functions | 
 | __builtin_tbegin_nofloat: |   | S/390 System z Built-in Functions | 
 | __builtin_tbegin_retry: |   | S/390 System z Built-in Functions | 
 | __builtin_tbegin_retry_nofloat: |   | S/390 System z Built-in Functions | 
 | __builtin_tend: |   | S/390 System z Built-in Functions | 
 | __builtin_tgmath: |   | Other Builtins | 
 | __builtin_thread_pointer: |   | SH Built-in Functions | 
 | __builtin_trap: |   | Other Builtins | 
 | __builtin_truncf128_round_to_odd: |   | Basic PowerPC Built-in Functions Available on ISA 3.0 | 
 | __builtin_tx_assist: |   | S/390 System z Built-in Functions | 
 | __builtin_tx_nesting_depth: |   | S/390 System z Built-in Functions | 
 | __builtin_types_compatible_p: |   | Other Builtins | 
 | __builtin_uaddll_overflow: |   | Integer Overflow Builtins | 
 | __builtin_uaddl_overflow: |   | Integer Overflow Builtins | 
 | __builtin_uadd_overflow: |   | Integer Overflow Builtins | 
 | __builtin_umulll_overflow: |   | Integer Overflow Builtins | 
 | __builtin_umull_overflow: |   | Integer Overflow Builtins | 
 | __builtin_umul_overflow: |   | Integer Overflow Builtins | 
 | __builtin_unreachable: |   | Other Builtins | 
 | __builtin_usubll_overflow: |   | Integer Overflow Builtins | 
 | __builtin_usubl_overflow: |   | Integer Overflow Builtins | 
 | __builtin_usub_overflow: |   | Integer Overflow Builtins | 
 | __builtin_va_arg_pack: |   | Constructing Calls | 
 | __builtin_va_arg_pack_len: |   | Constructing Calls | 
 | __builtin___clear_cache: |   | Other Builtins | 
 | __builtin___fprintf_chk: |   | Object Size Checking | 
 | __builtin___memcpy_chk: |   | Object Size Checking | 
 | __builtin___memmove_chk: |   | Object Size Checking | 
 | __builtin___mempcpy_chk: |   | Object Size Checking | 
 | __builtin___memset_chk: |   | Object Size Checking | 
 | __builtin___printf_chk: |   | Object Size Checking | 
 | __builtin___snprintf_chk: |   | Object Size Checking | 
 | __builtin___sprintf_chk: |   | Object Size Checking | 
 | __builtin___stpcpy_chk: |   | Object Size Checking | 
 | __builtin___strcat_chk: |   | Object Size Checking | 
 | __builtin___strcpy_chk: |   | Object Size Checking | 
 | __builtin___strncat_chk: |   | Object Size Checking | 
 | __builtin___strncpy_chk: |   | Object Size Checking | 
 | __builtin___vfprintf_chk: |   | Object Size Checking | 
 | __builtin___vprintf_chk: |   | Object Size Checking | 
 | __builtin___vsnprintf_chk: |   | Object Size Checking | 
 | __builtin___vsprintf_chk: |   | Object Size Checking | 
 | __complex__ keyword: |   | Complex | 
 | __declspec(dllexport): |   | Microsoft Windows Function Attributes | 
 | __declspec(dllimport): |   | Microsoft Windows Function Attributes | 
 | __ea SPU Named Address Spaces: |   | Named Address Spaces | 
 | __extension__: |   | Alternate Keywords | 
 | __far M32C Named Address Spaces: |   | Named Address Spaces | 
 | __far RL78 Named Address Spaces: |   | Named Address Spaces | 
 | __flash AVR Named Address Spaces: |   | Named Address Spaces | 
 | __flash1 AVR Named Address Spaces: |   | Named Address Spaces | 
 | __flash2 AVR Named Address Spaces: |   | Named Address Spaces | 
 | __flash3 AVR Named Address Spaces: |   | Named Address Spaces | 
 | __flash4 AVR Named Address Spaces: |   | Named Address Spaces | 
 | __flash5 AVR Named Address Spaces: |   | Named Address Spaces | 
 | __float128 data type: |   | Floating Types | 
 | __float80 data type: |   | Floating Types | 
 | __fp16 data type: |   | Half-Precision | 
 | __FUNCTION__ identifier: |   | Function Names | 
 | __func__ identifier: |   | Function Names | 
 | __ibm128 data type: |   | Floating Types | 
 | __imag__ keyword: |   | Complex | 
 | __int128 data types: |   | __int128 | 
 | __memx AVR Named Address Spaces: |   | Named Address Spaces | 
 | __PRETTY_FUNCTION__ identifier: |   | Function Names | 
 | __real__ keyword: |   | Complex | 
 | __seg_fs x86 named address space: |   | Named Address Spaces | 
 | __seg_gs x86 named address space: |   | Named Address Spaces | 
 | __STDC_HOSTED__: |   | Standards | 
 | __sync_add_and_fetch: |   | __sync Builtins | 
 | __sync_and_and_fetch: |   | __sync Builtins | 
 | __sync_bool_compare_and_swap: |   | __sync Builtins | 
 | __sync_fetch_and_add: |   | __sync Builtins | 
 | __sync_fetch_and_and: |   | __sync Builtins | 
 | __sync_fetch_and_nand: |   | __sync Builtins | 
 | __sync_fetch_and_or: |   | __sync Builtins | 
 | __sync_fetch_and_sub: |   | __sync Builtins | 
 | __sync_fetch_and_xor: |   | __sync Builtins | 
 | __sync_lock_release: |   | __sync Builtins | 
 | __sync_lock_test_and_set: |   | __sync Builtins | 
 | __sync_nand_and_fetch: |   | __sync Builtins | 
 | __sync_or_and_fetch: |   | __sync Builtins | 
 | __sync_sub_and_fetch: |   | __sync Builtins | 
 | __sync_synchronize: |   | __sync Builtins | 
 | __sync_val_compare_and_swap: |   | __sync Builtins | 
 | __sync_xor_and_fetch: |   | __sync Builtins | 
 | __thread: |   | Thread-Local | 
 
  | 
| A |  |  | 
 | AArch64 Options: |   | AArch64 Options | 
 | ABI: |   | Compatibility | 
 | abi_tag function attribute: |   | C++ Attributes | 
 | abi_tag type attribute: |   | C++ Attributes | 
 | abi_tag variable attribute: |   | C++ Attributes | 
 | abort: |   | Other Builtins | 
 | abs: |   | Other Builtins | 
 | absdata variable attribute, AVR: |   | AVR Variable Attributes | 
 | accessing volatiles: |   | Volatiles | 
 | accessing volatiles: |   | C++ Volatiles | 
 | acos: |   | Other Builtins | 
 | acosf: |   | Other Builtins | 
 | acosh: |   | Other Builtins | 
 | acoshf: |   | Other Builtins | 
 | acoshl: |   | Other Builtins | 
 | acosl: |   | Other Builtins | 
 | Ada: |   | G++ and GCC | 
 | Ada: |   | G++ and GCC | 
 | additional floating types: |   | Floating Types | 
 | address constraints: |   | Simple Constraints | 
 | address of a label: |   | Labels as Values | 
 | address variable attribute, AVR: |   | AVR Variable Attributes | 
 | address_operand: |   | Simple Constraints | 
 | alias function attribute: |   | Common Function Attributes | 
 | alias variable attribute: |   | Common Variable Attributes | 
 | aligned function attribute: |   | Common Function Attributes | 
 | aligned type attribute: |   | Common Type Attributes | 
 | aligned variable attribute: |   | Common Variable Attributes | 
 | alignment: |   | Alignment | 
 | alloca: |   | Other Builtins | 
 | alloca vs variable-length arrays: |   | Variable Length | 
 | alloc_align function attribute: |   | Common Function Attributes | 
 | alloc_size function attribute: |   | Common Function Attributes | 
 | alloc_size type attribute: |   | Common Type Attributes | 
 | alloc_size variable attribute: |   | Common Variable Attributes | 
 | Allow nesting in an interrupt handler on the Blackfin processor: |   | Blackfin Function Attributes | 
 | Altera Nios II options: |   | Nios II Options | 
 | alternate keywords: |   | Alternate Keywords | 
 | altivec type attribute, PowerPC: |   | PowerPC Type Attributes | 
 | altivec variable attribute, PowerPC: |   | PowerPC Variable Attributes | 
 | always_inline function attribute: |   | Common Function Attributes | 
 | AMD GCN Options: |   | AMD GCN Options | 
 | AMD1: |   | Standards | 
 | amdgpu_hsa_kernel function attribute, AMD GCN: |   | AMD GCN Function Attributes | 
 | ANSI C: |   | Standards | 
 | ANSI C standard: |   | Standards | 
 | ANSI C89: |   | Standards | 
 | ANSI support: |   | C Dialect Options | 
 | ANSI X3.159-1989: |   | Standards | 
 | apostrophes: |   | Incompatibilities | 
 | application binary interface: |   | Compatibility | 
 | ARC options: |   | ARC Options | 
 | arch= function attribute, AArch64: |   | AArch64 Function Attributes | 
 | arch= function attribute, ARM: |   | ARM Function Attributes | 
 | ARM options: |   | ARM Options | 
 | ARM [Annotated C++ Reference Manual]: |   | Backwards Compatibility | 
 | arrays of length zero: |   | Zero Length | 
 | arrays of variable length: |   | Variable Length | 
 | arrays, non-lvalue: |   | Subscripting | 
 | artificial function attribute: |   | Common Function Attributes | 
 | asin: |   | Other Builtins | 
 | asinf: |   | Other Builtins | 
 | asinh: |   | Other Builtins | 
 | asinhf: |   | Other Builtins | 
 | asinhl: |   | Other Builtins | 
 | asinl: |   | Other Builtins | 
 | asm assembler template: |   | Extended Asm | 
 | asm clobbers: |   | Extended Asm | 
 | asm constraints: |   | Constraints | 
 | asm expressions: |   | Extended Asm | 
 | asm flag output operands: |   | Extended Asm | 
 | asm goto labels: |   | Extended Asm | 
 | asm inline: |   | Size of an asm | 
 | asm input operands: |   | Extended Asm | 
 | asm keyword: |   | Using Assembly Language with C | 
 | asm output operands: |   | Extended Asm | 
 | asm scratch registers: |   | Extended Asm | 
 | asm volatile: |   | Extended Asm | 
 | assembler names for identifiers: |   | Asm Labels | 
 | assembly code, invalid: |   | Bug Criteria | 
 | assembly language in C: |   | Using Assembly Language with C | 
 | assembly language in C, basic: |   | Basic Asm | 
 | assembly language in C, extended: |   | Extended Asm | 
 | assume_aligned function attribute: |   | Common Function Attributes | 
 | atan: |   | Other Builtins | 
 | atan2: |   | Other Builtins | 
 | atan2f: |   | Other Builtins | 
 | atan2l: |   | Other Builtins | 
 | atanf: |   | Other Builtins | 
 | atanh: |   | Other Builtins | 
 | atanhf: |   | Other Builtins | 
 | atanhl: |   | Other Builtins | 
 | atanl: |   | Other Builtins | 
 | attribute of types: |   | Type Attributes | 
 | attribute of variables: |   | Variable Attributes | 
 | attribute syntax: |   | Attribute Syntax | 
 | autoincrement/decrement addressing: |   | Simple Constraints | 
 | automatic inline for C++ member fns: |   | Inline | 
 | aux variable attribute, ARC: |   | ARC Variable Attributes | 
 | AVR Options: |   | AVR Options | 
 
  | 
| B |  |  | 
 | Backwards Compatibility: |   | Backwards Compatibility | 
 | bank_switch function attribute, M32C: |   | M32C Function Attributes | 
 | base class members: |   | Name lookup | 
 | based type attribute, MeP: |   | MeP Type Attributes | 
 | based variable attribute, MeP: |   | MeP Variable Attributes | 
 | basic asm: |   | Basic Asm | 
 | bcmp: |   | Other Builtins | 
 | below100 variable attribute, Xstormy16: |   | Xstormy16 Variable Attributes | 
 | binary compatibility: |   | Compatibility | 
 | Binary constants using the ‘0b’ prefix: |   | Binary constants | 
 | Blackfin Options: |   | Blackfin Options | 
 | bound pointer to member function: |   | Bound member functions | 
 | branch-protection function attribute, AArch64: |   | AArch64 Function Attributes | 
 | break handler functions: |   | MicroBlaze Function Attributes | 
 | break_handler function attribute, MicroBlaze: |   | MicroBlaze Function Attributes | 
 | brk_interrupt function attribute, RL78: |   | RL78 Function Attributes | 
 | bug criteria: |   | Bug Criteria | 
 | bugs: |   | Bugs | 
 | bugs, known: |   | Trouble | 
 | built-in functions: |   | C Dialect Options | 
 | built-in functions: |   | Other Builtins | 
 | bzero: |   | Other Builtins | 
 
  | 
| C |  |  | 
 | C compilation options: |   | Invoking GCC | 
 | C intermediate output, nonexistent: |   | G++ and GCC | 
 | C language extensions: |   | C Extensions | 
 | C language, traditional: |   | Preprocessor Options | 
 | C standard: |   | Standards | 
 | C standards: |   | Standards | 
 | c++: |   | Invoking G++ | 
 | C++: |   | G++ and GCC | 
 | C++ comments: |   | C++ Comments | 
 | C++ interface and implementation headers: |   | C++ Interface | 
 | C++ language extensions: |   | C++ Extensions | 
 | C++ member fns, automatically inline: |   | Inline | 
 | C++ misunderstandings: |   | C++ Misunderstandings | 
 | C++ options, command-line: |   | C++ Dialect Options | 
 | C++ pragmas, effect on inlining: |   | C++ Interface | 
 | C++ source file suffixes: |   | Invoking G++ | 
 | C++ static data, declaring and defining: |   | Static Definitions | 
 | C-SKY Options: |   | C-SKY Options | 
 | C11: |   | Standards | 
 | C17: |   | Standards | 
 | C1X: |   | Standards | 
 | C2X: |   | Standards | 
 | C6X Options: |   | C6X Options | 
 | C89: |   | Standards | 
 | C90: |   | Standards | 
 | C94: |   | Standards | 
 | C95: |   | Standards | 
 | C99: |   | Standards | 
 | C9X: |   | Standards | 
 | cabs: |   | Other Builtins | 
 | cabsf: |   | Other Builtins | 
 | cabsl: |   | Other Builtins | 
 | cacos: |   | Other Builtins | 
 | cacosf: |   | Other Builtins | 
 | cacosh: |   | Other Builtins | 
 | cacoshf: |   | Other Builtins | 
 | cacoshl: |   | Other Builtins | 
 | cacosl: |   | Other Builtins | 
 | callee_pop_aggregate_return function attribute, x86: |   | x86 Function Attributes | 
 | calling functions through the function vector on SH2A: |   | SH Function Attributes | 
 | calloc: |   | Other Builtins | 
 | carg: |   | Other Builtins | 
 | cargf: |   | Other Builtins | 
 | cargl: |   | Other Builtins | 
 | case labels in initializers: |   | Designated Inits | 
 | case ranges: |   | Case Ranges | 
 | casin: |   | Other Builtins | 
 | casinf: |   | Other Builtins | 
 | casinh: |   | Other Builtins | 
 | casinhf: |   | Other Builtins | 
 | casinhl: |   | Other Builtins | 
 | casinl: |   | Other Builtins | 
 | cast to a union: |   | Cast to Union | 
 | catan: |   | Other Builtins | 
 | catanf: |   | Other Builtins | 
 | catanh: |   | Other Builtins | 
 | catanhf: |   | Other Builtins | 
 | catanhl: |   | Other Builtins | 
 | catanl: |   | Other Builtins | 
 | cb variable attribute, MeP: |   | MeP Variable Attributes | 
 | cbrt: |   | Other Builtins | 
 | cbrtf: |   | Other Builtins | 
 | cbrtl: |   | Other Builtins | 
 | ccos: |   | Other Builtins | 
 | ccosf: |   | Other Builtins | 
 | ccosh: |   | Other Builtins | 
 | ccoshf: |   | Other Builtins | 
 | ccoshl: |   | Other Builtins | 
 | ccosl: |   | Other Builtins | 
 | cdecl function attribute, x86-32: |   | x86 Function Attributes | 
 | ceil: |   | Other Builtins | 
 | ceilf: |   | Other Builtins | 
 | ceill: |   | Other Builtins | 
 | cexp: |   | Other Builtins | 
 | cexpf: |   | Other Builtins | 
 | cexpl: |   | Other Builtins | 
 | cf_check function attribute, x86: |   | x86 Function Attributes | 
 | character set, execution: |   | Preprocessor Options | 
 | character set, input: |   | Preprocessor Options | 
 | character set, input normalization: |   | Warning Options | 
 | character set, wide execution: |   | Preprocessor Options | 
 | cimag: |   | Other Builtins | 
 | cimagf: |   | Other Builtins | 
 | cimagl: |   | Other Builtins | 
 | cleanup variable attribute: |   | Common Variable Attributes | 
 | clog: |   | Other Builtins | 
 | clog10: |   | Other Builtins | 
 | clog10f: |   | Other Builtins | 
 | clog10l: |   | Other Builtins | 
 | clogf: |   | Other Builtins | 
 | clogl: |   | Other Builtins | 
 | cmodel= function attribute, AArch64: |   | AArch64 Function Attributes | 
 | COBOL: |   | G++ and GCC | 
 | code generation conventions: |   | Code Gen Options | 
 | code, mixed with declarations: |   | Mixed Declarations | 
 | cold function attribute: |   | Common Function Attributes | 
 | cold label attribute: |   | Label Attributes | 
 | command options: |   | Invoking GCC | 
 | comments, C++ style: |   | C++ Comments | 
 | common variable attribute: |   | Common Variable Attributes | 
 | comparison of signed and unsigned values, warning: |   | Warning Options | 
 | compilation statistics: |   | Developer Options | 
 | compiler bugs, reporting: |   | Bug Reporting | 
 | compiler compared to C++ preprocessor: |   | G++ and GCC | 
 | compiler options, C++: |   | C++ Dialect Options | 
 | compiler options, Objective-C and Objective-C++: |   | Objective-C and Objective-C++ Dialect Options | 
 | compiler version, specifying: |   | Invoking GCC | 
 | COMPILER_PATH: |   | Environment Variables | 
 | complex conjugation: |   | Complex | 
 | complex numbers: |   | Complex | 
 | compound literals: |   | Compound Literals | 
 | computed gotos: |   | Labels as Values | 
 | conditional expressions, extensions: |   | Conditionals | 
 | conflicting types: |   | Disappointments | 
 | conj: |   | Other Builtins | 
 | conjf: |   | Other Builtins | 
 | conjl: |   | Other Builtins | 
 | const applied to function: |   | Function Attributes | 
 | const function attribute: |   | Common Function Attributes | 
 | const qualifier: |   | Pointers to Arrays | 
 | constants in constraints: |   | Simple Constraints | 
 | constraint modifier characters: |   | Modifiers | 
 | constraint, matching: |   | Simple Constraints | 
 | constraints, asm: |   | Constraints | 
 | constraints, machine specific: |   | Machine Constraints | 
 | constructing calls: |   | Constructing Calls | 
 | constructor expressions: |   | Compound Literals | 
 | constructor function attribute: |   | Common Function Attributes | 
 | contributors: |   | Contributors | 
 | copy function attribute: |   | Common Function Attributes | 
 | copy type attribute: |   | Common Type Attributes | 
 | copy variable attribute: |   | Common Variable Attributes | 
 | copysign: |   | Other Builtins | 
 | copysignf: |   | Other Builtins | 
 | copysignl: |   | Other Builtins | 
 | core dump: |   | Bug Criteria | 
 | cos: |   | Other Builtins | 
 | cosf: |   | Other Builtins | 
 | cosh: |   | Other Builtins | 
 | coshf: |   | Other Builtins | 
 | coshl: |   | Other Builtins | 
 | cosl: |   | Other Builtins | 
 | CPATH: |   | Environment Variables | 
 | CPLUS_INCLUDE_PATH: |   | Environment Variables | 
 | cpow: |   | Other Builtins | 
 | cpowf: |   | Other Builtins | 
 | cpowl: |   | Other Builtins | 
 | cproj: |   | Other Builtins | 
 | cprojf: |   | Other Builtins | 
 | cprojl: |   | Other Builtins | 
 | cpu= function attribute, AArch64: |   | AArch64 Function Attributes | 
 | CR16 Options: |   | CR16 Options | 
 | creal: |   | Other Builtins | 
 | crealf: |   | Other Builtins | 
 | creall: |   | Other Builtins | 
 | CRIS Options: |   | CRIS Options | 
 | critical function attribute, MSP430: |   | MSP430 Function Attributes | 
 | cross compiling: |   | Invoking GCC | 
 | csin: |   | Other Builtins | 
 | csinf: |   | Other Builtins | 
 | csinh: |   | Other Builtins | 
 | csinhf: |   | Other Builtins | 
 | csinhl: |   | Other Builtins | 
 | csinl: |   | Other Builtins | 
 | csqrt: |   | Other Builtins | 
 | csqrtf: |   | Other Builtins | 
 | csqrtl: |   | Other Builtins | 
 | ctan: |   | Other Builtins | 
 | ctanf: |   | Other Builtins | 
 | ctanh: |   | Other Builtins | 
 | ctanhf: |   | Other Builtins | 
 | ctanhl: |   | Other Builtins | 
 | ctanl: |   | Other Builtins | 
 | C_INCLUDE_PATH: |   | Environment Variables | 
 
  | 
| D |  |  | 
 | D: |   | G++ and GCC | 
 | Darwin options: |   | Darwin Options | 
 | dcgettext: |   | Other Builtins | 
 | dd integer suffix: |   | Decimal Float | 
 | DD integer suffix: |   | Decimal Float | 
 | deallocating variable length arrays: |   | Variable Length | 
 | debug dump options: |   | Developer Options | 
 | debugging GCC: |   | Developer Options | 
 | debugging information options: |   | Debugging Options | 
 | decimal floating types: |   | Decimal Float | 
 | declaration scope: |   | Incompatibilities | 
 | declarations inside expressions: |   | Statement Exprs | 
 | declarations, mixed with code: |   | Mixed Declarations | 
 | declaring attributes of functions: |   | Function Attributes | 
 | declaring static data in C++: |   | Static Definitions | 
 | defining static data in C++: |   | Static Definitions | 
 | dependencies for make as output: |   | Environment Variables | 
 | dependencies for make as output: |   | Environment Variables | 
 | dependencies, make: |   | Preprocessor Options | 
 | DEPENDENCIES_OUTPUT: |   | Environment Variables | 
 | dependent name lookup: |   | Name lookup | 
 | deprecated enumerator attribute: |   | Enumerator Attributes | 
 | deprecated function attribute: |   | Common Function Attributes | 
 | deprecated type attribute: |   | Common Type Attributes | 
 | deprecated variable attribute: |   | Common Variable Attributes | 
 | designated initializers: |   | Designated Inits | 
 | designated_init type attribute: |   | Common Type Attributes | 
 | designator lists: |   | Designated Inits | 
 | designators: |   | Designated Inits | 
 | destructor function attribute: |   | Common Function Attributes | 
 | developer options: |   | Developer Options | 
 | df integer suffix: |   | Decimal Float | 
 | DF integer suffix: |   | Decimal Float | 
 | dgettext: |   | Other Builtins | 
 | diagnostic messages: |   | Diagnostic Message Formatting Options | 
 | dialect options: |   | C Dialect Options | 
 | diff-delete GCC_COLORS capability: |   | Diagnostic Message Formatting Options | 
 | diff-filename GCC_COLORS capability: |   | Diagnostic Message Formatting Options | 
 | diff-hunk GCC_COLORS capability: |   | Diagnostic Message Formatting Options | 
 | diff-insert GCC_COLORS capability: |   | Diagnostic Message Formatting Options | 
 | digits in constraint: |   | Simple Constraints | 
 | directory options: |   | Directory Options | 
 | disinterrupt function attribute, Epiphany: |   | Epiphany Function Attributes | 
 | disinterrupt function attribute, MeP: |   | MeP Function Attributes | 
 | dl integer suffix: |   | Decimal Float | 
 | DL integer suffix: |   | Decimal Float | 
 | dllexport function attribute: |   | Microsoft Windows Function Attributes | 
 | dllexport variable attribute: |   | Microsoft Windows Variable Attributes | 
 | dllimport function attribute: |   | Microsoft Windows Function Attributes | 
 | dllimport variable attribute: |   | Microsoft Windows Variable Attributes | 
 | dollar signs in identifier names: |   | Dollar Signs | 
 | double-word arithmetic: |   | Long Long | 
 | downward funargs: |   | Nested Functions | 
 | drem: |   | Other Builtins | 
 | dremf: |   | Other Builtins | 
 | dreml: |   | Other Builtins | 
 | dump options: |   | Developer Options | 
 
  | 
| E |  |  | 
 | ‘E’ in constraint: |   | Simple Constraints | 
 | earlyclobber operand: |   | Modifiers | 
 | eight-bit data on the H8/300, H8/300H, and H8S: |   | H8/300 Variable Attributes | 
 | eightbit_data variable attribute, H8/300: |   | H8/300 Variable Attributes | 
 | EIND: |   | AVR Options | 
 | either function attribute, MSP430: |   | MSP430 Function Attributes | 
 | either variable attribute, MSP430: |   | MSP430 Variable Attributes | 
 | empty structures: |   | Empty Structures | 
 | Enumerator Attributes: |   | Enumerator Attributes | 
 | environment variables: |   | Environment Variables | 
 | erf: |   | Other Builtins | 
 | erfc: |   | Other Builtins | 
 | erfcf: |   | Other Builtins | 
 | erfcl: |   | Other Builtins | 
 | erff: |   | Other Builtins | 
 | erfl: |   | Other Builtins | 
 | error function attribute: |   | Common Function Attributes | 
 | error GCC_COLORS capability: |   | Diagnostic Message Formatting Options | 
 | error messages: |   | Warnings and Errors | 
 | escaped newlines: |   | Escaped Newlines | 
 | exception function attribute: |   | NDS32 Function Attributes | 
 | exception handler functions, Blackfin: |   | Blackfin Function Attributes | 
 | exception handler functions, NDS32: |   | NDS32 Function Attributes | 
 | exception_handler function attribute: |   | Blackfin Function Attributes | 
 | exit: |   | Other Builtins | 
 | exp: |   | Other Builtins | 
 | exp10: |   | Other Builtins | 
 | exp10f: |   | Other Builtins | 
 | exp10l: |   | Other Builtins | 
 | exp2: |   | Other Builtins | 
 | exp2f: |   | Other Builtins | 
 | exp2l: |   | Other Builtins | 
 | expf: |   | Other Builtins | 
 | expl: |   | Other Builtins | 
 | explicit register variables: |   | Explicit Register Variables | 
 | expm1: |   | Other Builtins | 
 | expm1f: |   | Other Builtins | 
 | expm1l: |   | Other Builtins | 
 | expressions containing statements: |   | Statement Exprs | 
 | expressions, constructor: |   | Compound Literals | 
 | extended asm: |   | Extended Asm | 
 | extensible constraints: |   | Simple Constraints | 
 | extensions, ?:: |   | Conditionals | 
 | extensions, C language: |   | C Extensions | 
 | extensions, C++ language: |   | C++ Extensions | 
 | external declaration scope: |   | Incompatibilities | 
 | externally_visible function attribute: |   | Common Function Attributes | 
 | extra NOP instructions at the function entry point: |   | Common Function Attributes | 
 
  | 
| F |  |  | 
 | ‘F’ in constraint: |   | Simple Constraints | 
 | fabs: |   | Other Builtins | 
 | fabsf: |   | Other Builtins | 
 | fabsl: |   | Other Builtins | 
 | fallthrough statement attribute: |   | Statement Attributes | 
 | far function attribute, MeP: |   | MeP Function Attributes | 
 | far function attribute, MIPS: |   | MIPS Function Attributes | 
 | far type attribute, MeP: |   | MeP Type Attributes | 
 | far variable attribute, MeP: |   | MeP Variable Attributes | 
 | fastcall function attribute, x86-32: |   | x86 Function Attributes | 
 | fast_interrupt function attribute, M32C: |   | M32C Function Attributes | 
 | fast_interrupt function attribute, MicroBlaze: |   | MicroBlaze Function Attributes | 
 | fast_interrupt function attribute, RX: |   | RX Function Attributes | 
 | fatal signal: |   | Bug Criteria | 
 | fdim: |   | Other Builtins | 
 | fdimf: |   | Other Builtins | 
 | fdiml: |   | Other Builtins | 
 | FDL, GNU Free Documentation License: |   | GNU Free Documentation License | 
 | fentry_name function attribute, x86: |   | x86 Function Attributes | 
 | fentry_section function attribute, x86: |   | x86 Function Attributes | 
 | ffs: |   | Other Builtins | 
 | file name suffix: |   | Overall Options | 
 | file names: |   | Link Options | 
 | fix-cortex-a53-835769 function attribute, AArch64: |   | AArch64 Function Attributes | 
 | fixed-point types: |   | Fixed-Point | 
 | fixit-delete GCC_COLORS capability: |   | Diagnostic Message Formatting Options | 
 | fixit-insert GCC_COLORS capability: |   | Diagnostic Message Formatting Options | 
 | flatten function attribute: |   | Common Function Attributes | 
 | flexible array members: |   | Zero Length | 
 | float as function value type: |   | Incompatibilities | 
 | floating point precision: |   | Disappointments | 
 | floating-point precision: |   | Optimize Options | 
 | floor: |   | Other Builtins | 
 | floorf: |   | Other Builtins | 
 | floorl: |   | Other Builtins | 
 | fma: |   | Other Builtins | 
 | fmaf: |   | Other Builtins | 
 | fmal: |   | Other Builtins | 
 | fmax: |   | Other Builtins | 
 | fmaxf: |   | Other Builtins | 
 | fmaxl: |   | Other Builtins | 
 | fmin: |   | Other Builtins | 
 | fminf: |   | Other Builtins | 
 | fminl: |   | Other Builtins | 
 | fmod: |   | Other Builtins | 
 | fmodf: |   | Other Builtins | 
 | fmodl: |   | Other Builtins | 
 | force_align_arg_pointer function attribute, x86: |   | x86 Function Attributes | 
 | format function attribute: |   | Common Function Attributes | 
 | format_arg function attribute: |   | Common Function Attributes | 
 | Fortran: |   | G++ and GCC | 
 | forwarder_section function attribute, Epiphany: |   | Epiphany Function Attributes | 
 | forwarding calls: |   | Constructing Calls | 
 | fprintf: |   | Other Builtins | 
 | fprintf_unlocked: |   | Other Builtins | 
 | fputs: |   | Other Builtins | 
 | fputs_unlocked: |   | Other Builtins | 
 | FR30 Options: |   | FR30 Options | 
 | freestanding environment: |   | Standards | 
 | freestanding implementation: |   | Standards | 
 | frexp: |   | Other Builtins | 
 | frexpf: |   | Other Builtins | 
 | frexpl: |   | Other Builtins | 
 | FRV Options: |   | FRV Options | 
 | fscanf: |   | Other Builtins | 
 | fscanf, and constant strings: |   | Incompatibilities | 
 | FT32 Options: |   | FT32 Options | 
 | function addressability on the M32R/D: |   | M32R/D Function Attributes | 
 | function attributes: |   | Function Attributes | 
 | function pointers, arithmetic: |   | Pointer Arith | 
 | function prototype declarations: |   | Function Prototypes | 
 | function versions: |   | Function Multiversioning | 
 | function, size of pointer to: |   | Pointer Arith | 
 | functions in arbitrary sections: |   | Common Function Attributes | 
 | functions that are dynamically resolved: |   | Common Function Attributes | 
 | functions that are passed arguments in registers on x86-32: |   | x86 Function Attributes | 
 | functions that behave like malloc: |   | Common Function Attributes | 
 | functions that have no side effects: |   | Common Function Attributes | 
 | functions that have no side effects: |   | Common Function Attributes | 
 | functions that never return: |   | Common Function Attributes | 
 | functions that pop the argument stack on x86-32: |   | x86 Function Attributes | 
 | functions that pop the argument stack on x86-32: |   | x86 Function Attributes | 
 | functions that pop the argument stack on x86-32: |   | x86 Function Attributes | 
 | functions that pop the argument stack on x86-32: |   | x86 Function Attributes | 
 | functions that return more than once: |   | Common Function Attributes | 
 | functions with non-null pointer arguments: |   | Common Function Attributes | 
 | functions with printf, scanf, strftime or strfmon style arguments: |   | Common Function Attributes | 
 | function_return function attribute, x86: |   | x86 Function Attributes | 
 | function_vector function attribute, H8/300: |   | H8/300 Function Attributes | 
 | function_vector function attribute, M16C/M32C: |   | M32C Function Attributes | 
 | function_vector function attribute, SH: |   | SH Function Attributes | 
 
  | 
| G |  |  | 
 | ‘G’ in constraint: |   | Simple Constraints | 
 | ‘g’ in constraint: |   | Simple Constraints | 
 | g++: |   | Invoking G++ | 
 | G++: |   | G++ and GCC | 
 | gamma: |   | Other Builtins | 
 | gammaf: |   | Other Builtins | 
 | gammaf_r: |   | Other Builtins | 
 | gammal: |   | Other Builtins | 
 | gammal_r: |   | Other Builtins | 
 | gamma_r: |   | Other Builtins | 
 | GCC: |   | G++ and GCC | 
 | GCC command options: |   | Invoking GCC | 
 | GCC_COLORS environment variable: |   | Diagnostic Message Formatting Options | 
 | GCC_COMPARE_DEBUG: |   | Environment Variables | 
 | GCC_EXEC_PREFIX: |   | Environment Variables | 
 | gcc_struct type attribute, PowerPC: |   | PowerPC Type Attributes | 
 | gcc_struct type attribute, x86: |   | x86 Type Attributes | 
 | gcc_struct variable attribute, PowerPC: |   | PowerPC Variable Attributes | 
 | gcc_struct variable attribute, x86: |   | x86 Variable Attributes | 
 | gcov: |   | Instrumentation Options | 
 | general-regs-only function attribute, AArch64: |   | AArch64 Function Attributes | 
 | general-regs-only function attribute, ARM: |   | ARM Function Attributes | 
 | gettext: |   | Other Builtins | 
 | global offset table: |   | Code Gen Options | 
 | global register after longjmp: |   | Global Register Variables | 
 | global register variables: |   | Global Register Variables | 
 | GNAT: |   | G++ and GCC | 
 | GNU C Compiler: |   | G++ and GCC | 
 | GNU Compiler Collection: |   | G++ and GCC | 
 | gnu_inline function attribute: |   | Common Function Attributes | 
 | Go: |   | G++ and GCC | 
 | goto with computed label: |   | Labels as Values | 
 | gprof: |   | Instrumentation Options | 
 | grouping options: |   | Invoking GCC | 
 
  | 
| H |  |  | 
 | ‘H’ in constraint: |   | Simple Constraints | 
 | half-precision floating point: |   | Half-Precision | 
 | hardware models and configurations, specifying: |   | Submodel Options | 
 | hex floats: |   | Hex Floats | 
 | highlight, color: |   | Diagnostic Message Formatting Options | 
 | hk fixed-suffix: |   | Fixed-Point | 
 | HK fixed-suffix: |   | Fixed-Point | 
 | hosted environment: |   | Standards | 
 | hosted environment: |   | C Dialect Options | 
 | hosted environment: |   | C Dialect Options | 
 | hosted implementation: |   | Standards | 
 | hot function attribute: |   | Common Function Attributes | 
 | hot label attribute: |   | Label Attributes | 
 | hotpatch function attribute, S/390: |   | S/390 Function Attributes | 
 | HPPA Options: |   | HPPA Options | 
 | hr fixed-suffix: |   | Fixed-Point | 
 | HR fixed-suffix: |   | Fixed-Point | 
 | hypot: |   | Other Builtins | 
 | hypotf: |   | Other Builtins | 
 | hypotl: |   | Other Builtins | 
 
  | 
| I |  |  | 
 | ‘i’ in constraint: |   | Simple Constraints | 
 | ‘I’ in constraint: |   | Simple Constraints | 
 | IA-64 Options: |   | IA-64 Options | 
 | IBM RS/6000 and PowerPC Options: |   | RS/6000 and PowerPC Options | 
 | identifier names, dollar signs in: |   | Dollar Signs | 
 | identifiers, names in assembler code: |   | Asm Labels | 
 | ifunc function attribute: |   | Common Function Attributes | 
 | ilogb: |   | Other Builtins | 
 | ilogbf: |   | Other Builtins | 
 | ilogbl: |   | Other Builtins | 
 | imaxabs: |   | Other Builtins | 
 | implementation-defined behavior, C language: |   | C Implementation | 
 | implementation-defined behavior, C++ language: |   | C++ Implementation | 
 | implied #pragma implementation: |   | C++ Interface | 
 | incompatibilities of GCC: |   | Incompatibilities | 
 | increment operators: |   | Bug Criteria | 
 | index: |   | Other Builtins | 
 | indirect calls, ARC: |   | ARC Function Attributes | 
 | indirect calls, ARM: |   | ARM Function Attributes | 
 | indirect calls, Blackfin: |   | Blackfin Function Attributes | 
 | indirect calls, Epiphany: |   | Epiphany Function Attributes | 
 | indirect calls, MIPS: |   | MIPS Function Attributes | 
 | indirect calls, PowerPC: |   | PowerPC Function Attributes | 
 | indirect functions: |   | Common Function Attributes | 
 | indirect_branch function attribute, x86: |   | x86 Function Attributes | 
 | indirect_return function attribute, x86: |   | x86 Function Attributes | 
 | initializations in expressions: |   | Compound Literals | 
 | initializers with labeled elements: |   | Designated Inits | 
 | initializers, non-constant: |   | Initializers | 
 | init_priority variable attribute: |   | C++ Attributes | 
 | inline assembly language: |   | Using Assembly Language with C | 
 | inline automatic for C++ member fns: |   | Inline | 
 | inline functions: |   | Inline | 
 | inline functions, omission of: |   | Inline | 
 | inlining and C++ pragmas: |   | C++ Interface | 
 | installation trouble: |   | Trouble | 
 | instrumentation options: |   | Instrumentation Options | 
 | integrating function code: |   | Inline | 
 | interface and implementation headers, C++: |   | C++ Interface | 
 | intermediate C version, nonexistent: |   | G++ and GCC | 
 | interrupt function attribute, ARC: |   | ARC Function Attributes | 
 | interrupt function attribute, ARM: |   | ARM Function Attributes | 
 | interrupt function attribute, AVR: |   | AVR Function Attributes | 
 | interrupt function attribute, C-SKY: |   | C-SKY Function Attributes | 
 | interrupt function attribute, CR16: |   | CR16 Function Attributes | 
 | interrupt function attribute, Epiphany: |   | Epiphany Function Attributes | 
 | interrupt function attribute, M32C: |   | M32C Function Attributes | 
 | interrupt function attribute, M32R/D: |   | M32R/D Function Attributes | 
 | interrupt function attribute, m68k: |   | m68k Function Attributes | 
 | interrupt function attribute, MeP: |   | MeP Function Attributes | 
 | interrupt function attribute, MIPS: |   | MIPS Function Attributes | 
 | interrupt function attribute, MSP430: |   | MSP430 Function Attributes | 
 | interrupt function attribute, NDS32: |   | NDS32 Function Attributes | 
 | interrupt function attribute, RISC-V: |   | RISC-V Function Attributes | 
 | interrupt function attribute, RL78: |   | RL78 Function Attributes | 
 | interrupt function attribute, RX: |   | RX Function Attributes | 
 | interrupt function attribute, V850: |   | V850 Function Attributes | 
 | interrupt function attribute, Visium: |   | Visium Function Attributes | 
 | interrupt function attribute, x86: |   | x86 Function Attributes | 
 | interrupt function attribute, Xstormy16: |   | Xstormy16 Function Attributes | 
 | interrupt_handler function attribute, Blackfin: |   | Blackfin Function Attributes | 
 | interrupt_handler function attribute, H8/300: |   | H8/300 Function Attributes | 
 | interrupt_handler function attribute, m68k: |   | m68k Function Attributes | 
 | interrupt_handler function attribute, MicroBlaze: |   | MicroBlaze Function Attributes | 
 | interrupt_handler function attribute, SH: |   | SH Function Attributes | 
 | interrupt_handler function attribute, V850: |   | V850 Function Attributes | 
 | interrupt_thread function attribute, fido: |   | m68k Function Attributes | 
 | introduction: |   | Top | 
 | invalid assembly code: |   | Bug Criteria | 
 | invalid input: |   | Bug Criteria | 
 | invoking g++: |   | Invoking G++ | 
 | io variable attribute, AVR: |   | AVR Variable Attributes | 
 | io variable attribute, MeP: |   | MeP Variable Attributes | 
 | io_low variable attribute, AVR: |   | AVR Variable Attributes | 
 | isalnum: |   | Other Builtins | 
 | isalpha: |   | Other Builtins | 
 | isascii: |   | Other Builtins | 
 | isblank: |   | Other Builtins | 
 | iscntrl: |   | Other Builtins | 
 | isdigit: |   | Other Builtins | 
 | isgraph: |   | Other Builtins | 
 | islower: |   | Other Builtins | 
 | ISO 9899: |   | Standards | 
 | ISO C: |   | Standards | 
 | ISO C standard: |   | Standards | 
 | ISO C11: |   | Standards | 
 | ISO C17: |   | Standards | 
 | ISO C1X: |   | Standards | 
 | ISO C2X: |   | Standards | 
 | ISO C90: |   | Standards | 
 | ISO C94: |   | Standards | 
 | ISO C95: |   | Standards | 
 | ISO C99: |   | Standards | 
 | ISO C9X: |   | Standards | 
 | ISO support: |   | C Dialect Options | 
 | ISO/IEC 9899: |   | Standards | 
 | isprint: |   | Other Builtins | 
 | ispunct: |   | Other Builtins | 
 | isr function attribute, ARM: |   | ARM Function Attributes | 
 | isr function attribute, C-SKY: |   | C-SKY Function Attributes | 
 | isspace: |   | Other Builtins | 
 | isupper: |   | Other Builtins | 
 | iswalnum: |   | Other Builtins | 
 | iswalpha: |   | Other Builtins | 
 | iswblank: |   | Other Builtins | 
 | iswcntrl: |   | Other Builtins | 
 | iswdigit: |   | Other Builtins | 
 | iswgraph: |   | Other Builtins | 
 | iswlower: |   | Other Builtins | 
 | iswprint: |   | Other Builtins | 
 | iswpunct: |   | Other Builtins | 
 | iswspace: |   | Other Builtins | 
 | iswupper: |   | Other Builtins | 
 | iswxdigit: |   | Other Builtins | 
 | isxdigit: |   | Other Builtins | 
 
  | 
| J |  |  | 
 | j0: |   | Other Builtins | 
 | j0f: |   | Other Builtins | 
 | j0l: |   | Other Builtins | 
 | j1: |   | Other Builtins | 
 | j1f: |   | Other Builtins | 
 | j1l: |   | Other Builtins | 
 | jli_always function attribute, ARC: |   | ARC Function Attributes | 
 | jli_fixed function attribute, ARC: |   | ARC Function Attributes | 
 | jn: |   | Other Builtins | 
 | jnf: |   | Other Builtins | 
 | jnl: |   | Other Builtins | 
 
  | 
| K |  |  | 
 | k fixed-suffix: |   | Fixed-Point | 
 | K fixed-suffix: |   | Fixed-Point | 
 | keep_interrupts_masked function attribute, MIPS: |   | MIPS Function Attributes | 
 | kernel attribute, Nvidia PTX: |   | Nvidia PTX Function Attributes | 
 | keywords, alternate: |   | Alternate Keywords | 
 | known causes of trouble: |   | Trouble | 
 | kspisusp function attribute, Blackfin: |   | Blackfin Function Attributes | 
 
  | 
| L |  |  | 
 | l1_data variable attribute, Blackfin: |   | Blackfin Variable Attributes | 
 | l1_data_A variable attribute, Blackfin: |   | Blackfin Variable Attributes | 
 | l1_data_B variable attribute, Blackfin: |   | Blackfin Variable Attributes | 
 | l1_text function attribute, Blackfin: |   | Blackfin Function Attributes | 
 | l2 function attribute, Blackfin: |   | Blackfin Function Attributes | 
 | l2 variable attribute, Blackfin: |   | Blackfin Variable Attributes | 
 | Label Attributes: |   | Label Attributes | 
 | labeled elements in initializers: |   | Designated Inits | 
 | labels as values: |   | Labels as Values | 
 | labs: |   | Other Builtins | 
 | LANG: |   | Environment Variables | 
 | LANG: |   | Environment Variables | 
 | language dialect options: |   | C Dialect Options | 
 | LC_ALL: |   | Environment Variables | 
 | LC_CTYPE: |   | Environment Variables | 
 | LC_MESSAGES: |   | Environment Variables | 
 | ldexp: |   | Other Builtins | 
 | ldexpf: |   | Other Builtins | 
 | ldexpl: |   | Other Builtins | 
 | leaf function attribute: |   | Common Function Attributes | 
 | length-zero arrays: |   | Zero Length | 
 | lgamma: |   | Other Builtins | 
 | lgammaf: |   | Other Builtins | 
 | lgammaf_r: |   | Other Builtins | 
 | lgammal: |   | Other Builtins | 
 | lgammal_r: |   | Other Builtins | 
 | lgamma_r: |   | Other Builtins | 
 | Libraries: |   | Link Options | 
 | LIBRARY_PATH: |   | Environment Variables | 
 | link options: |   | Link Options | 
 | linker script: |   | Link Options | 
 | lk fixed-suffix: |   | Fixed-Point | 
 | LK fixed-suffix: |   | Fixed-Point | 
 | LL integer suffix: |   | Long Long | 
 | llabs: |   | Other Builtins | 
 | llk fixed-suffix: |   | Fixed-Point | 
 | LLK fixed-suffix: |   | Fixed-Point | 
 | llr fixed-suffix: |   | Fixed-Point | 
 | LLR fixed-suffix: |   | Fixed-Point | 
 | llrint: |   | Other Builtins | 
 | llrintf: |   | Other Builtins | 
 | llrintl: |   | Other Builtins | 
 | llround: |   | Other Builtins | 
 | llroundf: |   | Other Builtins | 
 | llroundl: |   | Other Builtins | 
 | LM32 options: |   | LM32 Options | 
 | load address instruction: |   | Simple Constraints | 
 | local labels: |   | Local Labels | 
 | local variables in macros: |   | Typeof | 
 | local variables, specifying registers: |   | Local Register Variables | 
 | locale: |   | Environment Variables | 
 | locale definition: |   | Environment Variables | 
 | locus GCC_COLORS capability: |   | Diagnostic Message Formatting Options | 
 | log: |   | Other Builtins | 
 | log10: |   | Other Builtins | 
 | log10f: |   | Other Builtins | 
 | log10l: |   | Other Builtins | 
 | log1p: |   | Other Builtins | 
 | log1pf: |   | Other Builtins | 
 | log1pl: |   | Other Builtins | 
 | log2: |   | Other Builtins | 
 | log2f: |   | Other Builtins | 
 | log2l: |   | Other Builtins | 
 | logb: |   | Other Builtins | 
 | logbf: |   | Other Builtins | 
 | logbl: |   | Other Builtins | 
 | logf: |   | Other Builtins | 
 | logl: |   | Other Builtins | 
 | long long data types: |   | Long Long | 
 | longcall function attribute, Blackfin: |   | Blackfin Function Attributes | 
 | longcall function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | longjmp: |   | Global Register Variables | 
 | longjmp incompatibilities: |   | Incompatibilities | 
 | longjmp warnings: |   | Warning Options | 
 | long_call function attribute, ARC: |   | ARC Function Attributes | 
 | long_call function attribute, ARM: |   | ARM Function Attributes | 
 | long_call function attribute, Epiphany: |   | Epiphany Function Attributes | 
 | long_call function attribute, MIPS: |   | MIPS Function Attributes | 
 | lower function attribute, MSP430: |   | MSP430 Function Attributes | 
 | lower variable attribute, MSP430: |   | MSP430 Variable Attributes | 
 | lr fixed-suffix: |   | Fixed-Point | 
 | LR fixed-suffix: |   | Fixed-Point | 
 | lrint: |   | Other Builtins | 
 | lrintf: |   | Other Builtins | 
 | lrintl: |   | Other Builtins | 
 | lround: |   | Other Builtins | 
 | lroundf: |   | Other Builtins | 
 | lroundl: |   | Other Builtins | 
 
  | 
| M |  |  | 
 | ‘m’ in constraint: |   | Simple Constraints | 
 | M32C options: |   | M32C Options | 
 | M32R/D options: |   | M32R/D Options | 
 | M680x0 options: |   | M680x0 Options | 
 | machine specific constraints: |   | Machine Constraints | 
 | machine-dependent options: |   | Submodel Options | 
 | macro with variable arguments: |   | Variadic Macros | 
 | macros, inline alternative: |   | Inline | 
 | macros, local labels: |   | Local Labels | 
 | macros, local variables in: |   | Typeof | 
 | macros, statements in expressions: |   | Statement Exprs | 
 | macros, types of arguments: |   | Typeof | 
 | make: |   | Preprocessor Options | 
 | malloc: |   | Other Builtins | 
 | malloc function attribute: |   | Common Function Attributes | 
 | matching constraint: |   | Simple Constraints | 
 | may_alias type attribute: |   | Common Type Attributes | 
 | MCore options: |   | MCore Options | 
 | medium_call function attribute, ARC: |   | ARC Function Attributes | 
 | member fns, automatically inline: |   | Inline | 
 | memchr: |   | Other Builtins | 
 | memcmp: |   | Other Builtins | 
 | memcpy: |   | Other Builtins | 
 | memory references in constraints: |   | Simple Constraints | 
 | mempcpy: |   | Other Builtins | 
 | memset: |   | Other Builtins | 
 | MeP options: |   | MeP Options | 
 | Mercury: |   | G++ and GCC | 
 | message formatting: |   | Diagnostic Message Formatting Options | 
 | messages, warning: |   | Warning Options | 
 | messages, warning and error: |   | Warnings and Errors | 
 | MicroBlaze Options: |   | MicroBlaze Options | 
 | micromips function attribute: |   | MIPS Function Attributes | 
 | middle-operands, omitted: |   | Conditionals | 
 | MIPS options: |   | MIPS Options | 
 | mips16 function attribute, MIPS: |   | MIPS Function Attributes | 
 | misunderstandings in C++: |   | C++ Misunderstandings | 
 | mixed declarations and code: |   | Mixed Declarations | 
 | mixing assembly language and C: |   | Using Assembly Language with C | 
 | mktemp, and constant strings: |   | Incompatibilities | 
 | MMIX Options: |   | MMIX Options | 
 | MN10300 options: |   | MN10300 Options | 
 | mode type attribute: |   | Common Type Attributes | 
 | mode variable attribute: |   | Common Variable Attributes | 
 | model function attribute, M32R/D: |   | M32R/D Function Attributes | 
 | model variable attribute, IA-64: |   | IA-64 Variable Attributes | 
 | model-name variable attribute, M32R/D: |   | M32R/D Variable Attributes | 
 | modf: |   | Other Builtins | 
 | modff: |   | Other Builtins | 
 | modfl: |   | Other Builtins | 
 | modifiers in constraints: |   | Modifiers | 
 | Moxie Options: |   | Moxie Options | 
 | MSP430 Options: |   | MSP430 Options | 
 | ms_abi function attribute, x86: |   | x86 Function Attributes | 
 | ms_hook_prologue function attribute, x86: |   | x86 Function Attributes | 
 | ms_struct type attribute, PowerPC: |   | PowerPC Type Attributes | 
 | ms_struct type attribute, x86: |   | x86 Type Attributes | 
 | ms_struct variable attribute, PowerPC: |   | PowerPC Variable Attributes | 
 | ms_struct variable attribute, x86: |   | x86 Variable Attributes | 
 | multiple alternative constraints: |   | Multi-Alternative | 
 | multiprecision arithmetic: |   | Long Long | 
 
  | 
| N |  |  | 
 | ‘n’ in constraint: |   | Simple Constraints | 
 | naked function attribute, ARM: |   | ARM Function Attributes | 
 | naked function attribute, AVR: |   | AVR Function Attributes | 
 | naked function attribute, C-SKY: |   | C-SKY Function Attributes | 
 | naked function attribute, MCORE: |   | MCORE Function Attributes | 
 | naked function attribute, MSP430: |   | MSP430 Function Attributes | 
 | naked function attribute, NDS32: |   | NDS32 Function Attributes | 
 | naked function attribute, RISC-V: |   | RISC-V Function Attributes | 
 | naked function attribute, RL78: |   | RL78 Function Attributes | 
 | naked function attribute, RX: |   | RX Function Attributes | 
 | naked function attribute, SPU: |   | SPU Function Attributes | 
 | naked function attribute, x86: |   | x86 Function Attributes | 
 | Named Address Spaces: |   | Named Address Spaces | 
 | names used in assembler code: |   | Asm Labels | 
 | naming convention, implementation headers: |   | C++ Interface | 
 | NDS32 Options: |   | NDS32 Options | 
 | near function attribute, MeP: |   | MeP Function Attributes | 
 | near function attribute, MIPS: |   | MIPS Function Attributes | 
 | near type attribute, MeP: |   | MeP Type Attributes | 
 | near variable attribute, MeP: |   | MeP Variable Attributes | 
 | nearbyint: |   | Other Builtins | 
 | nearbyintf: |   | Other Builtins | 
 | nearbyintl: |   | Other Builtins | 
 | nested function attribute, NDS32: |   | NDS32 Function Attributes | 
 | nested functions: |   | Nested Functions | 
 | nested_ready function attribute, NDS32: |   | NDS32 Function Attributes | 
 | nesting function attribute, Blackfin: |   | Blackfin Function Attributes | 
 | newlines (escaped): |   | Escaped Newlines | 
 | nextafter: |   | Other Builtins | 
 | nextafterf: |   | Other Builtins | 
 | nextafterl: |   | Other Builtins | 
 | nexttoward: |   | Other Builtins | 
 | nexttowardf: |   | Other Builtins | 
 | nexttowardl: |   | Other Builtins | 
 | NFC: |   | Warning Options | 
 | NFKC: |   | Warning Options | 
 | Nios II options: |   | Nios II Options | 
 | nmi function attribute, NDS32: |   | NDS32 Function Attributes | 
 | NMI handler functions on the Blackfin processor: |   | Blackfin Function Attributes | 
 | nmi_handler function attribute, Blackfin: |   | Blackfin Function Attributes | 
 | nocf_check function attribute: |   | x86 Function Attributes | 
 | noclone function attribute: |   | Common Function Attributes | 
 | nocommon variable attribute: |   | Common Variable Attributes | 
 | nocompression function attribute, MIPS: |   | MIPS Function Attributes | 
 | noinit variable attribute, MSP430: |   | MSP430 Variable Attributes | 
 | noinline function attribute: |   | Common Function Attributes | 
 | noipa function attribute: |   | Common Function Attributes | 
 | nomicromips function attribute: |   | MIPS Function Attributes | 
 | nomips16 function attribute, MIPS: |   | MIPS Function Attributes | 
 | non-constant initializers: |   | Initializers | 
 | non-static inline function: |   | Inline | 
 | nonlocal gotos: |   | Nonlocal Gotos | 
 | nonnull function attribute: |   | Common Function Attributes | 
 | nonstring variable attribute: |   | Common Variable Attributes | 
 | noplt function attribute: |   | Common Function Attributes | 
 | noreturn function attribute: |   | Common Function Attributes | 
 | nosave_low_regs function attribute, SH: |   | SH Function Attributes | 
 | note GCC_COLORS capability: |   | Diagnostic Message Formatting Options | 
 | nothrow function attribute: |   | Common Function Attributes | 
 | notshared type attribute, ARM: |   | ARM Type Attributes | 
 | not_nested function attribute, NDS32: |   | NDS32 Function Attributes | 
 | no_caller_saved_registers function attribute, x86: |   | x86 Function Attributes | 
 | no_gccisr function attribute, AVR: |   | AVR Function Attributes | 
 | no_icf function attribute: |   | Common Function Attributes | 
 | no_instrument_function function attribute: |   | Common Function Attributes | 
 | no_profile_instrument_function function attribute: |   | Common Function Attributes | 
 | no_reorder function attribute: |   | Common Function Attributes | 
 | no_sanitize function attribute: |   | Common Function Attributes | 
 | no_sanitize_address function attribute: |   | Common Function Attributes | 
 | no_sanitize_thread function attribute: |   | Common Function Attributes | 
 | no_sanitize_undefined function attribute: |   | Common Function Attributes | 
 | no_split_stack function attribute: |   | Common Function Attributes | 
 | no_stack_limit function attribute: |   | Common Function Attributes | 
 | Nvidia PTX options: |   | Nvidia PTX Options | 
 | nvptx options: |   | Nvidia PTX Options | 
 
  | 
| O |  |  | 
 | ‘o’ in constraint: |   | Simple Constraints | 
 | OBJC_INCLUDE_PATH: |   | Environment Variables | 
 | Objective-C: |   | G++ and GCC | 
 | Objective-C: |   | Standards | 
 | Objective-C and Objective-C++ options, command-line: |   | Objective-C and Objective-C++ Dialect Options | 
 | Objective-C++: |   | G++ and GCC | 
 | Objective-C++: |   | Standards | 
 | offsettable address: |   | Simple Constraints | 
 | old-style function definitions: |   | Function Prototypes | 
 | omit-leaf-frame-pointer function attribute, AArch64: |   | AArch64 Function Attributes | 
 | omitted middle-operands: |   | Conditionals | 
 | open coding: |   | Inline | 
 | OpenACC accelerator programming: |   | C Dialect Options | 
 | OpenACC accelerator programming: |   | C Dialect Options | 
 | OpenMP parallel: |   | C Dialect Options | 
 | OpenMP SIMD: |   | C Dialect Options | 
 | OpenRISC Options: |   | OpenRISC Options | 
 | operand constraints, asm: |   | Constraints | 
 | optimize function attribute: |   | Common Function Attributes | 
 | optimize options: |   | Optimize Options | 
 | options to control diagnostics formatting: |   | Diagnostic Message Formatting Options | 
 | options to control warnings: |   | Warning Options | 
 | options, C++: |   | C++ Dialect Options | 
 | options, code generation: |   | Code Gen Options | 
 | options, debugging: |   | Debugging Options | 
 | options, dialect: |   | C Dialect Options | 
 | options, directory search: |   | Directory Options | 
 | options, GCC command: |   | Invoking GCC | 
 | options, grouping: |   | Invoking GCC | 
 | options, linking: |   | Link Options | 
 | options, Objective-C and Objective-C++: |   | Objective-C and Objective-C++ Dialect Options | 
 | options, optimization: |   | Optimize Options | 
 | options, order: |   | Invoking GCC | 
 | options, preprocessor: |   | Preprocessor Options | 
 | options, profiling: |   | Instrumentation Options | 
 | options, program instrumentation: |   | Instrumentation Options | 
 | options, run-time error checking: |   | Instrumentation Options | 
 | order of evaluation, side effects: |   | Non-bugs | 
 | order of options: |   | Invoking GCC | 
 | OS_main function attribute, AVR: |   | AVR Function Attributes | 
 | OS_task function attribute, AVR: |   | AVR Function Attributes | 
 | other register constraints: |   | Simple Constraints | 
 | output file option: |   | Overall Options | 
 | overloaded virtual function, warning: |   | C++ Dialect Options | 
 
  | 
| P |  |  | 
 | ‘p’ in constraint: |   | Simple Constraints | 
 | packed type attribute: |   | Common Type Attributes | 
 | packed variable attribute: |   | Common Variable Attributes | 
 | parameter forward declaration: |   | Variable Length | 
 | partial_save function attribute, NDS32: |   | NDS32 Function Attributes | 
 | patchable_function_entry function attribute: |   | Common Function Attributes | 
 | pcs function attribute, ARM: |   | ARM Function Attributes | 
 | PDP-11 Options: |   | PDP-11 Options | 
 | persistent variable attribute, MSP430: |   | MSP430 Variable Attributes | 
 | PIC: |   | Code Gen Options | 
 | picoChip options: |   | picoChip Options | 
 | pmf: |   | Bound member functions | 
 | pointer arguments: |   | Common Function Attributes | 
 | pointer arguments in variadic functions: |   | Variadic Pointer Args | 
 | pointer to member function: |   | Bound member functions | 
 | pointers to arrays: |   | Pointers to Arrays | 
 | portions of temporary objects, pointers to: |   | Temporaries | 
 | pow: |   | Other Builtins | 
 | pow10: |   | Other Builtins | 
 | pow10f: |   | Other Builtins | 
 | pow10l: |   | Other Builtins | 
 | PowerPC options: |   | PowerPC Options | 
 | powf: |   | Other Builtins | 
 | powl: |   | Other Builtins | 
 | pragma GCC ivdep: |   | Loop-Specific Pragmas | 
 | pragma GCC optimize: |   | Function Specific Option Pragmas | 
 | pragma GCC pop_options: |   | Function Specific Option Pragmas | 
 | pragma GCC push_options: |   | Function Specific Option Pragmas | 
 | pragma GCC reset_options: |   | Function Specific Option Pragmas | 
 | pragma GCC target: |   | Function Specific Option Pragmas | 
 | pragma GCC unroll n: |   | Loop-Specific Pragmas | 
 | pragma, address: |   | M32C Pragmas | 
 | pragma, align: |   | Solaris Pragmas | 
 | pragma, call: |   | MeP Pragmas | 
 | pragma, coprocessor available: |   | MeP Pragmas | 
 | pragma, coprocessor call_saved: |   | MeP Pragmas | 
 | pragma, coprocessor subclass: |   | MeP Pragmas | 
 | pragma, custom io_volatile: |   | MeP Pragmas | 
 | pragma, diagnostic: |   | Diagnostic Pragmas | 
 | pragma, diagnostic: |   | Diagnostic Pragmas | 
 | pragma, diagnostic: |   | Diagnostic Pragmas | 
 | pragma, diagnostic: |   | Diagnostic Pragmas | 
 | pragma, disinterrupt: |   | MeP Pragmas | 
 | pragma, fini: |   | Solaris Pragmas | 
 | pragma, init: |   | Solaris Pragmas | 
 | pragma, longcall: |   | RS/6000 and PowerPC Pragmas | 
 | pragma, long_calls: |   | ARM Pragmas | 
 | pragma, long_calls_off: |   | ARM Pragmas | 
 | pragma, mark: |   | Darwin Pragmas | 
 | pragma, memregs: |   | M32C Pragmas | 
 | pragma, no_long_calls: |   | ARM Pragmas | 
 | pragma, options align: |   | Darwin Pragmas | 
 | pragma, pop_macro: |   | Push/Pop Macro Pragmas | 
 | pragma, push_macro: |   | Push/Pop Macro Pragmas | 
 | pragma, redefine_extname: |   | Symbol-Renaming Pragmas | 
 | pragma, segment: |   | Darwin Pragmas | 
 | pragma, unused: |   | Darwin Pragmas | 
 | pragma, visibility: |   | Visibility Pragmas | 
 | pragma, weak: |   | Weak Pragmas | 
 | pragmas: |   | Pragmas | 
 | pragmas in C++, effect on inlining: |   | C++ Interface | 
 | pragmas, interface and implementation: |   | C++ Interface | 
 | pragmas, warning of unknown: |   | Warning Options | 
 | precompiled headers: |   | Precompiled Headers | 
 | preprocessing numbers: |   | Incompatibilities | 
 | preprocessing tokens: |   | Incompatibilities | 
 | preprocessor options: |   | Preprocessor Options | 
 | printf: |   | Other Builtins | 
 | printf_unlocked: |   | Other Builtins | 
 | prof: |   | Instrumentation Options | 
 | profiling options: |   | Instrumentation Options | 
 | progmem variable attribute, AVR: |   | AVR Variable Attributes | 
 | program instrumentation options: |   | Instrumentation Options | 
 | promotion of formal parameters: |   | Function Prototypes | 
 | pure function attribute: |   | Common Function Attributes | 
 | push address instruction: |   | Simple Constraints | 
 | putchar: |   | Other Builtins | 
 | puts: |   | Other Builtins | 
 
  | 
| Q |  |  | 
 | q floating point suffix: |   | Floating Types | 
 | Q floating point suffix: |   | Floating Types | 
 | qsort, and global register variables: |   | Global Register Variables | 
 | quote GCC_COLORS capability: |   | Diagnostic Message Formatting Options | 
 
  | 
| R |  |  | 
 | r fixed-suffix: |   | Fixed-Point | 
 | R fixed-suffix: |   | Fixed-Point | 
 | ‘r’ in constraint: |   | Simple Constraints | 
 | RAMPD: |   | AVR Options | 
 | RAMPX: |   | AVR Options | 
 | RAMPY: |   | AVR Options | 
 | RAMPZ: |   | AVR Options | 
 | range1 GCC_COLORS capability: |   | Diagnostic Message Formatting Options | 
 | range2 GCC_COLORS capability: |   | Diagnostic Message Formatting Options | 
 | ranges in case statements: |   | Case Ranges | 
 | read-only strings: |   | Incompatibilities | 
 | reentrant function attribute, MSP430: |   | MSP430 Function Attributes | 
 | register variable after longjmp: |   | Global Register Variables | 
 | registers for local variables: |   | Local Register Variables | 
 | registers in constraints: |   | Simple Constraints | 
 | registers, global allocation: |   | Global Register Variables | 
 | registers, global variables in: |   | Global Register Variables | 
 | regparm function attribute, x86: |   | x86 Function Attributes | 
 | relocation truncated to fit (ColdFire): |   | M680x0 Options | 
 | relocation truncated to fit (MIPS): |   | MIPS Options | 
 | remainder: |   | Other Builtins | 
 | remainderf: |   | Other Builtins | 
 | remainderl: |   | Other Builtins | 
 | remquo: |   | Other Builtins | 
 | remquof: |   | Other Builtins | 
 | remquol: |   | Other Builtins | 
 | renesas function attribute, SH: |   | SH Function Attributes | 
 | reordering, warning: |   | C++ Dialect Options | 
 | reporting bugs: |   | Bugs | 
 | resbank function attribute, SH: |   | SH Function Attributes | 
 | reset function attribute, NDS32: |   | NDS32 Function Attributes | 
 | reset handler functions: |   | NDS32 Function Attributes | 
 | rest argument (in macro): |   | Variadic Macros | 
 | restricted pointers: |   | Restricted Pointers | 
 | restricted references: |   | Restricted Pointers | 
 | restricted this pointer: |   | Restricted Pointers | 
 | returns_nonnull function attribute: |   | Common Function Attributes | 
 | returns_twice function attribute: |   | Common Function Attributes | 
 | rindex: |   | Other Builtins | 
 | rint: |   | Other Builtins | 
 | rintf: |   | Other Builtins | 
 | rintl: |   | Other Builtins | 
 | RISC-V Options: |   | RISC-V Options | 
 | RL78 Options: |   | RL78 Options | 
 | round: |   | Other Builtins | 
 | roundf: |   | Other Builtins | 
 | roundl: |   | Other Builtins | 
 | RS/6000 and PowerPC Options: |   | RS/6000 and PowerPC Options | 
 | RTTI: |   | Vague Linkage | 
 | run-time error checking options: |   | Instrumentation Options | 
 | run-time options: |   | Code Gen Options | 
 | RX Options: |   | RX Options | 
 
  | 
| S |  |  | 
 | ‘s’ in constraint: |   | Simple Constraints | 
 | S/390 and zSeries Options: |   | S/390 and zSeries Options | 
 | saddr variable attribute, RL78: |   | RL78 Variable Attributes | 
 | save all registers on the Blackfin: |   | Blackfin Function Attributes | 
 | save all registers on the H8/300, H8/300H, and H8S: |   | H8/300 Function Attributes | 
 | saveall function attribute, Blackfin: |   | Blackfin Function Attributes | 
 | saveall function attribute, H8/300: |   | H8/300 Function Attributes | 
 | save_all function attribute, NDS32: |   | NDS32 Function Attributes | 
 | save_volatiles function attribute, MicroBlaze: |   | MicroBlaze Function Attributes | 
 | scalar_storage_order type attribute: |   | Common Type Attributes | 
 | scalb: |   | Other Builtins | 
 | scalbf: |   | Other Builtins | 
 | scalbl: |   | Other Builtins | 
 | scalbln: |   | Other Builtins | 
 | scalblnf: |   | Other Builtins | 
 | scalblnf: |   | Other Builtins | 
 | scalbn: |   | Other Builtins | 
 | scalbnf: |   | Other Builtins | 
 | scanf, and constant strings: |   | Incompatibilities | 
 | scanfnl: |   | Other Builtins | 
 | scope of a variable length array: |   | Variable Length | 
 | scope of declaration: |   | Disappointments | 
 | scope of external declarations: |   | Incompatibilities | 
 | Score Options: |   | Score Options | 
 | sda variable attribute, V850: |   | V850 Variable Attributes | 
 | search path: |   | Directory Options | 
 | section function attribute: |   | Common Function Attributes | 
 | section variable attribute: |   | Common Variable Attributes | 
 | secure_call function attribute, ARC: |   | ARC Function Attributes | 
 | selectany variable attribute: |   | Microsoft Windows Variable Attributes | 
 | sentinel function attribute: |   | Common Function Attributes | 
 | setjmp: |   | Global Register Variables | 
 | setjmp incompatibilities: |   | Incompatibilities | 
 | shared attribute, Nvidia PTX: |   | Nvidia PTX Variable Attributes | 
 | shared strings: |   | Incompatibilities | 
 | shared variable attribute: |   | Microsoft Windows Variable Attributes | 
 | shortcall function attribute, Blackfin: |   | Blackfin Function Attributes | 
 | shortcall function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | short_call function attribute, ARC: |   | ARC Function Attributes | 
 | short_call function attribute, ARM: |   | ARM Function Attributes | 
 | short_call function attribute, Epiphany: |   | Epiphany Function Attributes | 
 | short_call function attribute, MIPS: |   | MIPS Function Attributes | 
 | side effect in ?:: |   | Conditionals | 
 | side effects, macro argument: |   | Statement Exprs | 
 | side effects, order of evaluation: |   | Non-bugs | 
 | sign-return-address function attribute, AArch64: |   | AArch64 Function Attributes | 
 | signal function attribute, AVR: |   | AVR Function Attributes | 
 | signbit: |   | Other Builtins | 
 | signbitd128: |   | Other Builtins | 
 | signbitd32: |   | Other Builtins | 
 | signbitd64: |   | Other Builtins | 
 | signbitf: |   | Other Builtins | 
 | signbitl: |   | Other Builtins | 
 | signed and unsigned values, comparison warning: |   | Warning Options | 
 | significand: |   | Other Builtins | 
 | significandf: |   | Other Builtins | 
 | significandl: |   | Other Builtins | 
 | SIMD: |   | C Dialect Options | 
 | simd function attribute: |   | Common Function Attributes | 
 | simple constraints: |   | Simple Constraints | 
 | sin: |   | Other Builtins | 
 | sincos: |   | Other Builtins | 
 | sincosf: |   | Other Builtins | 
 | sincosl: |   | Other Builtins | 
 | sinf: |   | Other Builtins | 
 | sinh: |   | Other Builtins | 
 | sinhf: |   | Other Builtins | 
 | sinhl: |   | Other Builtins | 
 | sinl: |   | Other Builtins | 
 | sizeof: |   | Typeof | 
 | smaller data references: |   | M32R/D Options | 
 | smaller data references: |   | Nios II Options | 
 | smaller data references (PowerPC): |   | RS/6000 and PowerPC Options | 
 | snprintf: |   | Other Builtins | 
 | Solaris 2 options: |   | Solaris 2 Options | 
 | SOURCE_DATE_EPOCH: |   | Environment Variables | 
 | SPARC options: |   | SPARC Options | 
 | Spec Files: |   | Spec Files | 
 | specified registers: |   | Explicit Register Variables | 
 | specifying compiler version and target machine: |   | Invoking GCC | 
 | specifying hardware config: |   | Submodel Options | 
 | specifying machine version: |   | Invoking GCC | 
 | specifying registers for local variables: |   | Local Register Variables | 
 | speed of compilation: |   | Precompiled Headers | 
 | sprintf: |   | Other Builtins | 
 | SPU options: |   | SPU Options | 
 | spu_vector type attribute, SPU: |   | SPU Type Attributes | 
 | spu_vector variable attribute, SPU: |   | SPU Variable Attributes | 
 | sp_switch function attribute, SH: |   | SH Function Attributes | 
 | sqrt: |   | Other Builtins | 
 | sqrtf: |   | Other Builtins | 
 | sqrtl: |   | Other Builtins | 
 | sscanf: |   | Other Builtins | 
 | sscanf, and constant strings: |   | Incompatibilities | 
 | sseregparm function attribute, x86: |   | x86 Function Attributes | 
 | stack_protect function attribute: |   | Common Function Attributes | 
 | Statement Attributes: |   | Statement Attributes | 
 | statements inside expressions: |   | Statement Exprs | 
 | static data in C++, declaring and defining: |   | Static Definitions | 
 | stdcall function attribute, x86-32: |   | x86 Function Attributes | 
 | stpcpy: |   | Other Builtins | 
 | stpncpy: |   | Other Builtins | 
 | strcasecmp: |   | Other Builtins | 
 | strcat: |   | Other Builtins | 
 | strchr: |   | Other Builtins | 
 | strcmp: |   | Other Builtins | 
 | strcpy: |   | Other Builtins | 
 | strcspn: |   | Other Builtins | 
 | strdup: |   | Other Builtins | 
 | strfmon: |   | Other Builtins | 
 | strftime: |   | Other Builtins | 
 | strict-align function attribute, AArch64: |   | AArch64 Function Attributes | 
 | string constants: |   | Incompatibilities | 
 | strlen: |   | Other Builtins | 
 | strncasecmp: |   | Other Builtins | 
 | strncat: |   | Other Builtins | 
 | strncmp: |   | Other Builtins | 
 | strncpy: |   | Other Builtins | 
 | strndup: |   | Other Builtins | 
 | strnlen: |   | Other Builtins | 
 | strpbrk: |   | Other Builtins | 
 | strrchr: |   | Other Builtins | 
 | strspn: |   | Other Builtins | 
 | strstr: |   | Other Builtins | 
 | struct: |   | Unnamed Fields | 
 | struct __htm_tdb: |   | S/390 System z Built-in Functions | 
 | structures: |   | Incompatibilities | 
 | structures, constructor expression: |   | Compound Literals | 
 | submodel options: |   | Submodel Options | 
 | subscripting: |   | Subscripting | 
 | subscripting and function values: |   | Subscripting | 
 | suffixes for C++ source: |   | Invoking G++ | 
 | SUNPRO_DEPENDENCIES: |   | Environment Variables | 
 | suppressing warnings: |   | Warning Options | 
 | surprises in C++: |   | C++ Misunderstandings | 
 | syntax checking: |   | Warning Options | 
 | syscall_linkage function attribute, IA-64: |   | IA-64 Function Attributes | 
 | system headers, warnings from: |   | Warning Options | 
 | sysv_abi function attribute, x86: |   | x86 Function Attributes | 
 
  | 
| T |  |  | 
 | tan: |   | Other Builtins | 
 | tanf: |   | Other Builtins | 
 | tanh: |   | Other Builtins | 
 | tanhf: |   | Other Builtins | 
 | tanhl: |   | Other Builtins | 
 | tanl: |   | Other Builtins | 
 | target function attribute: |   | Common Function Attributes | 
 | target function attribute: |   | ARM Function Attributes | 
 | target function attribute: |   | Nios II Function Attributes | 
 | target function attribute: |   | PowerPC Function Attributes | 
 | target function attribute: |   | S/390 Function Attributes | 
 | target function attribute: |   | x86 Function Attributes | 
 | target machine, specifying: |   | Invoking GCC | 
 | target("3dnow") function attribute, x86: |   | x86 Function Attributes | 
 | target("3dnowa") function attribute, x86: |   | x86 Function Attributes | 
 | target("abm") function attribute, x86: |   | x86 Function Attributes | 
 | target("adx") function attribute, x86: |   | x86 Function Attributes | 
 | target("aes") function attribute, x86: |   | x86 Function Attributes | 
 | target("align-stringops") function attribute, x86: |   | x86 Function Attributes | 
 | target("altivec") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("arch=ARCH") function attribute, x86: |   | x86 Function Attributes | 
 | target("arm") function attribute, ARM: |   | ARM Function Attributes | 
 | target("avoid-indexed-addresses") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("avx") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx2") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx5124fmaps") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx5124vnniw") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx512bitalg") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx512bw") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx512cd") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx512dq") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx512er") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx512f") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx512ifma") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx512pf") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx512vbmi") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx512vbmi2") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx512vl") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx512vnni") function attribute, x86: |   | x86 Function Attributes | 
 | target("avx512vpopcntdq") function attribute, x86: |   | x86 Function Attributes | 
 | target("bmi") function attribute, x86: |   | x86 Function Attributes | 
 | target("bmi2") function attribute, x86: |   | x86 Function Attributes | 
 | target("cld") function attribute, x86: |   | x86 Function Attributes | 
 | target("cldemote") function attribute, x86: |   | x86 Function Attributes | 
 | target("clflushopt") function attribute, x86: |   | x86 Function Attributes | 
 | target("clwb") function attribute, x86: |   | x86 Function Attributes | 
 | target("clzero") function attribute, x86: |   | x86 Function Attributes | 
 | target("cmpb") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("cpu=CPU") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("crc32") function attribute, x86: |   | x86 Function Attributes | 
 | target("custom-fpu-cfg=name") function attribute, Nios II: |   | Nios II Function Attributes | 
 | target("custom-insn=N") function attribute, Nios II: |   | Nios II Function Attributes | 
 | target("cx16") function attribute, x86: |   | x86 Function Attributes | 
 | target("default") function attribute, x86: |   | x86 Function Attributes | 
 | target("dlmzb") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("f16c") function attribute, x86: |   | x86 Function Attributes | 
 | target("fancy-math-387") function attribute, x86: |   | x86 Function Attributes | 
 | target("fma") function attribute, x86: |   | x86 Function Attributes | 
 | target("fma4") function attribute, x86: |   | x86 Function Attributes | 
 | target("fpmath=FPMATH") function attribute, x86: |   | x86 Function Attributes | 
 | target("fprnd") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("fpu=") function attribute, ARM: |   | ARM Function Attributes | 
 | target("friz") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("fsgsbase") function attribute, x86: |   | x86 Function Attributes | 
 | target("fxsr") function attribute, x86: |   | x86 Function Attributes | 
 | target("gfni") function attribute, x86: |   | x86 Function Attributes | 
 | target("hard-dfp") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("hle") function attribute, x86: |   | x86 Function Attributes | 
 | target("ieee-fp") function attribute, x86: |   | x86 Function Attributes | 
 | target("inline-all-stringops") function attribute, x86: |   | x86 Function Attributes | 
 | target("inline-stringops-dynamically") function attribute, x86: |   | x86 Function Attributes | 
 | target("isel") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("longcall") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("lwp") function attribute, x86: |   | x86 Function Attributes | 
 | target("lzcnt") function attribute, x86: |   | x86 Function Attributes | 
 | target("mfcrf") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("mfpgpr") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("mmx") function attribute, x86: |   | x86 Function Attributes | 
 | target("movbe") function attribute, x86: |   | x86 Function Attributes | 
 | target("movdir64b") function attribute, x86: |   | x86 Function Attributes | 
 | target("movdiri") function attribute, x86: |   | x86 Function Attributes | 
 | target("mulhw") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("multiple") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("mwaitx") function attribute, x86: |   | x86 Function Attributes | 
 | target("no-custom-insn") function attribute, Nios II: |   | Nios II Function Attributes | 
 | target("paired") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("pclmul") function attribute, x86: |   | x86 Function Attributes | 
 | target("pconfig") function attribute, x86: |   | x86 Function Attributes | 
 | target("pku") function attribute, x86: |   | x86 Function Attributes | 
 | target("popcnt") function attribute, x86: |   | x86 Function Attributes | 
 | target("popcntb") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("popcntd") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("powerpc-gfxopt") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("powerpc-gpopt") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("prefetchwt1") function attribute, x86: |   | x86 Function Attributes | 
 | target("prfchw") function attribute, x86: |   | x86 Function Attributes | 
 | target("ptwrite") function attribute, x86: |   | x86 Function Attributes | 
 | target("rdpid") function attribute, x86: |   | x86 Function Attributes | 
 | target("rdrnd") function attribute, x86: |   | x86 Function Attributes | 
 | target("rdseed") function attribute, x86: |   | x86 Function Attributes | 
 | target("recip") function attribute, x86: |   | x86 Function Attributes | 
 | target("recip-precision") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("rtm") function attribute, x86: |   | x86 Function Attributes | 
 | target("sahf") function attribute, x86: |   | x86 Function Attributes | 
 | target("sgx") function attribute, x86: |   | x86 Function Attributes | 
 | target("sha") function attribute, x86: |   | x86 Function Attributes | 
 | target("shstk") function attribute, x86: |   | x86 Function Attributes | 
 | target("sse") function attribute, x86: |   | x86 Function Attributes | 
 | target("sse2") function attribute, x86: |   | x86 Function Attributes | 
 | target("sse3") function attribute, x86: |   | x86 Function Attributes | 
 | target("sse4") function attribute, x86: |   | x86 Function Attributes | 
 | target("sse4.1") function attribute, x86: |   | x86 Function Attributes | 
 | target("sse4.2") function attribute, x86: |   | x86 Function Attributes | 
 | target("sse4a") function attribute, x86: |   | x86 Function Attributes | 
 | target("ssse3") function attribute, x86: |   | x86 Function Attributes | 
 | target("string") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("tbm") function attribute, x86: |   | x86 Function Attributes | 
 | target("thumb") function attribute, ARM: |   | ARM Function Attributes | 
 | target("tune=TUNE") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("tune=TUNE") function attribute, x86: |   | x86 Function Attributes | 
 | target("update") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("vaes") function attribute, x86: |   | x86 Function Attributes | 
 | target("vpclmulqdq") function attribute, x86: |   | x86 Function Attributes | 
 | target("vsx") function attribute, PowerPC: |   | PowerPC Function Attributes | 
 | target("waitpkg") function attribute, x86: |   | x86 Function Attributes | 
 | target("wbnoinvd") function attribute, x86: |   | x86 Function Attributes | 
 | target("xop") function attribute, x86: |   | x86 Function Attributes | 
 | target("xsave") function attribute, x86: |   | x86 Function Attributes | 
 | target("xsavec") function attribute, x86: |   | x86 Function Attributes | 
 | target("xsaveopt") function attribute, x86: |   | x86 Function Attributes | 
 | target("xsaves") function attribute, x86: |   | x86 Function Attributes | 
 | target-dependent options: |   | Submodel Options | 
 | target_clones function attribute: |   | Common Function Attributes | 
 | TC1: |   | Standards | 
 | TC2: |   | Standards | 
 | TC3: |   | Standards | 
 | tda variable attribute, V850: |   | V850 Variable Attributes | 
 | Technical Corrigenda: |   | Standards | 
 | Technical Corrigendum 1: |   | Standards | 
 | Technical Corrigendum 2: |   | Standards | 
 | Technical Corrigendum 3: |   | Standards | 
 | template instantiation: |   | Template Instantiation | 
 | temporaries, lifetime of: |   | Temporaries | 
 | tentative definitions: |   | Code Gen Options | 
 | tgamma: |   | Other Builtins | 
 | tgammaf: |   | Other Builtins | 
 | tgammal: |   | Other Builtins | 
 | thiscall function attribute, x86-32: |   | x86 Function Attributes | 
 | Thread-Local Storage: |   | Thread-Local | 
 | thunks: |   | Nested Functions | 
 | TILE-Gx options: |   | TILE-Gx Options | 
 | TILEPro options: |   | TILEPro Options | 
 | tiny data section on the H8/300H and H8S: |   | H8/300 Variable Attributes | 
 | tiny type attribute, MeP: |   | MeP Type Attributes | 
 | tiny variable attribute, MeP: |   | MeP Variable Attributes | 
 | tiny_data variable attribute, H8/300: |   | H8/300 Variable Attributes | 
 | TLS: |   | Thread-Local | 
 | tls-dialect= function attribute, AArch64: |   | AArch64 Function Attributes | 
 | tls_model variable attribute: |   | Common Variable Attributes | 
 | TMPDIR: |   | Environment Variables | 
 | toascii: |   | Other Builtins | 
 | tolower: |   | Other Builtins | 
 | toupper: |   | Other Builtins | 
 | towlower: |   | Other Builtins | 
 | towupper: |   | Other Builtins | 
 | traditional C language: |   | Preprocessor Options | 
 | transparent_union type attribute: |   | Common Type Attributes | 
 | trapa_handler function attribute, SH: |   | SH Function Attributes | 
 | trap_exit function attribute, SH: |   | SH Function Attributes | 
 | trunc: |   | Other Builtins | 
 | truncf: |   | Other Builtins | 
 | truncl: |   | Other Builtins | 
 | tune= function attribute, AArch64: |   | AArch64 Function Attributes | 
 | two-stage name lookup: |   | Name lookup | 
 | type alignment: |   | Alignment | 
 | type attributes: |   | Type Attributes | 
 | type-diff GCC_COLORS capability: |   | Diagnostic Message Formatting Options | 
 | typedef names as function parameters: |   | Incompatibilities | 
 | typeof: |   | Typeof | 
 | type_info: |   | Vague Linkage | 
 
  | 
| U |  |  | 
 | uhk fixed-suffix: |   | Fixed-Point | 
 | UHK fixed-suffix: |   | Fixed-Point | 
 | uhr fixed-suffix: |   | Fixed-Point | 
 | UHR fixed-suffix: |   | Fixed-Point | 
 | uk fixed-suffix: |   | Fixed-Point | 
 | UK fixed-suffix: |   | Fixed-Point | 
 | ulk fixed-suffix: |   | Fixed-Point | 
 | ULK fixed-suffix: |   | Fixed-Point | 
 | ULL integer suffix: |   | Long Long | 
 | ullk fixed-suffix: |   | Fixed-Point | 
 | ULLK fixed-suffix: |   | Fixed-Point | 
 | ullr fixed-suffix: |   | Fixed-Point | 
 | ULLR fixed-suffix: |   | Fixed-Point | 
 | ulr fixed-suffix: |   | Fixed-Point | 
 | ULR fixed-suffix: |   | Fixed-Point | 
 | uncached type attribute, ARC: |   | ARC Type Attributes | 
 | undefined behavior: |   | Bug Criteria | 
 | undefined function value: |   | Bug Criteria | 
 | underscores in variables in macros: |   | Typeof | 
 | union: |   | Unnamed Fields | 
 | union, casting to a: |   | Cast to Union | 
 | unions: |   | Incompatibilities | 
 | unknown pragmas, warning: |   | Warning Options | 
 | unresolved references and -nodefaultlibs: |   | Link Options | 
 | unresolved references and -nostdlib: |   | Link Options | 
 | unused function attribute: |   | Common Function Attributes | 
 | unused label attribute: |   | Label Attributes | 
 | unused type attribute: |   | Common Type Attributes | 
 | unused variable attribute: |   | Common Variable Attributes | 
 | upper function attribute, MSP430: |   | MSP430 Function Attributes | 
 | upper variable attribute, MSP430: |   | MSP430 Variable Attributes | 
 | ur fixed-suffix: |   | Fixed-Point | 
 | UR fixed-suffix: |   | Fixed-Point | 
 | used function attribute: |   | Common Function Attributes | 
 | used variable attribute: |   | Common Variable Attributes | 
 | User stack pointer in interrupts on the Blackfin: |   | Blackfin Function Attributes | 
 | use_debug_exception_return function attribute, MIPS: |   | MIPS Function Attributes | 
 | use_shadow_register_set function attribute, MIPS: |   | MIPS Function Attributes | 
 
  | 
| V |  |  | 
 | ‘V’ in constraint: |   | Simple Constraints | 
 | V850 Options: |   | V850 Options | 
 | vague linkage: |   | Vague Linkage | 
 | value after longjmp: |   | Global Register Variables | 
 | variable addressability on the M32R/D: |   | M32R/D Variable Attributes | 
 | variable alignment: |   | Alignment | 
 | variable attributes: |   | Variable Attributes | 
 | variable number of arguments: |   | Variadic Macros | 
 | variable-length array in a structure: |   | Variable Length | 
 | variable-length array scope: |   | Variable Length | 
 | variable-length arrays: |   | Variable Length | 
 | variables in specified registers: |   | Explicit Register Variables | 
 | variables, local, in macros: |   | Typeof | 
 | variadic functions, pointer arguments: |   | Variadic Pointer Args | 
 | variadic macros: |   | Variadic Macros | 
 | VAX options: |   | VAX Options | 
 | vector function attribute, RX: |   | RX Function Attributes | 
 | vector types, using with x86 intrinsics: |   | Vector Extensions | 
 | vector_size type attribute: |   | Common Type Attributes | 
 | vector_size variable attribute: |   | Common Variable Attributes | 
 | version_id function attribute, IA-64: |   | IA-64 Function Attributes | 
 | vfprintf: |   | Other Builtins | 
 | vfscanf: |   | Other Builtins | 
 | visibility function attribute: |   | Common Function Attributes | 
 | visibility type attribute: |   | Common Type Attributes | 
 | visibility variable attribute: |   | Common Variable Attributes | 
 | Visium options: |   | Visium Options | 
 | VLAs: |   | Variable Length | 
 | vliw function attribute, MeP: |   | MeP Function Attributes | 
 | void pointers, arithmetic: |   | Pointer Arith | 
 | void, size of pointer to: |   | Pointer Arith | 
 | volatile access: |   | Volatiles | 
 | volatile access: |   | C++ Volatiles | 
 | volatile applied to function: |   | Function Attributes | 
 | volatile asm: |   | Extended Asm | 
 | volatile read: |   | Volatiles | 
 | volatile read: |   | C++ Volatiles | 
 | volatile write: |   | Volatiles | 
 | volatile write: |   | C++ Volatiles | 
 | vprintf: |   | Other Builtins | 
 | vscanf: |   | Other Builtins | 
 | vsnprintf: |   | Other Builtins | 
 | vsprintf: |   | Other Builtins | 
 | vsscanf: |   | Other Builtins | 
 | vtable: |   | Vague Linkage | 
 | VxWorks Options: |   | VxWorks Options | 
 
  | 
| W |  |  | 
 | w floating point suffix: |   | Floating Types | 
 | W floating point suffix: |   | Floating Types | 
 | wakeup function attribute, MSP430: |   | MSP430 Function Attributes | 
 | warm function attribute, NDS32: |   | NDS32 Function Attributes | 
 | warning for comparison of signed and unsigned values: |   | Warning Options | 
 | warning for overloaded virtual function: |   | C++ Dialect Options | 
 | warning for reordering of member initializers: |   | C++ Dialect Options | 
 | warning for unknown pragmas: |   | Warning Options | 
 | warning function attribute: |   | Common Function Attributes | 
 | warning GCC_COLORS capability: |   | Diagnostic Message Formatting Options | 
 | warning messages: |   | Warning Options | 
 | warnings from system headers: |   | Warning Options | 
 | warnings vs errors: |   | Warnings and Errors | 
 | warn_if_not_aligned type attribute: |   | Common Type Attributes | 
 | warn_if_not_aligned variable attribute: |   | Common Variable Attributes | 
 | warn_unused type attribute: |   | C++ Attributes | 
 | warn_unused_result function attribute: |   | Common Function Attributes | 
 | weak function attribute: |   | Common Function Attributes | 
 | weak variable attribute: |   | Common Variable Attributes | 
 | weakref function attribute: |   | Common Function Attributes | 
 | whitespace: |   | Incompatibilities | 
 | Windows Options for x86: |   | x86 Windows Options | 
 
  | 
| X |  |  | 
 | ‘X’ in constraint: |   | Simple Constraints | 
 | X3.159-1989: |   | Standards | 
 | x86 named address spaces: |   | Named Address Spaces | 
 | x86 Options: |   | x86 Options | 
 | x86 Windows Options: |   | x86 Windows Options | 
 | Xstormy16 Options: |   | Xstormy16 Options | 
 | Xtensa Options: |   | Xtensa Options | 
 
  | 
| Y |  |  | 
 | y0: |   | Other Builtins | 
 | y0f: |   | Other Builtins | 
 | y0l: |   | Other Builtins | 
 | y1: |   | Other Builtins | 
 | y1f: |   | Other Builtins | 
 | y1l: |   | Other Builtins | 
 | yn: |   | Other Builtins | 
 | ynf: |   | Other Builtins | 
 | ynl: |   | Other Builtins | 
 
  | 
| Z |  |  | 
 | zda variable attribute, V850: |   | V850 Variable Attributes | 
 | zero-length arrays: |   | Zero Length | 
 | zero-size structures: |   | Empty Structures | 
 | zSeries options: |   | zSeries Options | 
 
  |