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__align __alignof__ __ALIGNOF__ __asm __forceinline __global_reg __inline __int64 __INTADDR__ __irq __packed __pure __smc __softfp __svc __svc_indirect __svc_indirect_r7 __value_in_regs __weak __writeonly __declspec attributes __declspec(dllexport) __declspec(dllimport) __declspec(noinline) __declspec(noreturn) __declspec(nothrow) __declspec(notshared) __declspec(thread) Function attributes __attribute__((alias)) __attribute__((always_inline)) __attribute__((const)) __attribute__((deprecated)) __attribute__((malloc)) __attribute__((noinline)) __attribute__((noreturn)) __attribute__((pure)) __attribute__((section)) __attribute__((unused)) __attribute__((used)) __attribute__((weak)) Type attributes __attribute__((aligned)) __attribute((packed)) __attribute__((transparent_union)) Variable attributes __attribute__((alias)) __attribute__((at(address))) __attribute__((aligned)) __attribute__((deprecated)) __attribute__((packed)) __attribute__((section)) __attribute__((transparent_union)) __attribute__((unused)) __attribute__((used)) __attribute__((weak)) __attribute__((zero_init)) Pragmas #pragma [no_]anon_unions #pragma arm #pragma arm section [section_sort_list] #pragma diag_default tag[,tag,...] #pragma diag_error tag[,tag,...] #pragma diag_remark tag[,tag,...] #pragma diag_suppress tag[,tag,...] #pragma diag_warning tag[, tag, ...] #pragma [no_]exceptions_unwind #pragma hdrstop #pragma import symbol_name #pragma [no_]inline #pragma no_pch #pragma Onum #pragma once #pragma Ospace #pragma Otime #pragma pop #pragma push #pragma [no_]softfp_linkage #pragma unroll [(n)] #pragma unroll_completely #pragma thumb Instruction intrinsics __breakpoint __builtin_clz __builtin_constant_p __builtin_expect __builtin_frame_address __builtin_return_address __builtin_popcount __cdp __clrex __clz __current_pc __current_sp __disable_fiq __disable_irq __enable_fiq __enable_irq __fabs __fabsf __force_stores __ldrex __ldrt __memory_changed __nop __pld __pli __qadd __qdbl __qsub __rbit __rev __return_address __ror __schedule_barrier __semihost __sev __sqrt __sqrtf __ssat __strex __strt __swp __usat __wfe __wfi __yield ARMv6 SIMD intrinsics ETSI basic operations C55x intrinsics Named register variables Compiler predefines Predefined macros Function names C and C++ Implementation Details Via File Syntax Standard C Implementation Definition Standard C++ Implementation Definition C and C++ Compiler Implementation Limits__value_in_regs
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Home > Compiler-specific Features > Keywords and operators > __value_in_regs | |||
The __value_in_regs qualifier instructs the compiler to return a structure of up to four integer words in integer registers or up to four floats or doubles in floating‑point registers rather than using memory.
__value_in_regs is a function qualifier. It affects the type of a function.
__value_in_regs return-type function-name([argument-list]);
Where:
return‑typeis the type of a structure of up to four words in size.
Declaring a function __value_in_regs can be useful when calling functions that return more than one result.
A C++ function cannot return a __value_in_regs structure if the structure requires copy constructing.
If a virtual function declared as __value_in_regs is to be overridden, the overriding function must also be declared as __value_in_regs. If the functions do not match, the compiler generates an error.
Where the structure returned in a function qualified by __value_in_regs is too big, a warning is produced and the __value_in_regs structure is then ignored.
typedef struct int64_struct
{
unsigned int lo;
unsigned int hi;
} int64_struct;
__value_in_regs extern
int64_struct mul64(unsigned a, unsigned b);
__value_in_regs in the Compiler User Guide.
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