_InterlockedExchange Intrinsic Functions
Microsoft Specific
Generates an atomic instruction to set a specified value.
long _InterlockedExchange(
long volatile * Target,
long Value
);
long _InterlockedExchange_acq(
long volatile * Target,
long Value
);
long _InterlockedExchange_HLEAcquire(
long volatile * Target,
long Value
);
long _InterlockedExchange_HLERelease(
long volatile * Target,
long Value
);
long _InterlockedExchange_nf(
long volatile * Target,
long Value
);
long _InterlockedExchange_rel(
long volatile * Target,
long Value
);
char _InterlockedExchange8(
char volatile * Target,
char Value
);
char _InterlockedExchange8_acq(
char volatile * Target,
char Value
);
char _InterlockedExchange8_nf(
char volatile * Target,
char Value
);
char _InterlockedExchange8_rel(
char volatile * Target,
char Value
);
short _InterlockedExchange16(
short volatile * Target,
short Value
);
short _InterlockedExchange16_acq(
short volatile * Target,
short Value
);
short _InterlockedExchange16_nf(
short volatile * Target,
short Value
);
short _InterlockedExchange16_rel(
short volatile * Target,
short Value
);
__int64 _InterlockedExchange64(
__int64 volatile * Target,
__int64 Value
);
__int64 _InterlockedExchange64_acq(
__int64 volatile * Target,
__int64 Value
);
__int64 _InterlockedExchange64_HLEAcquire(
__int64 volatile * Target,
__int64 Value
);
__int64 _InterlockedExchange64_HLERelease(
__int64 volatile * Target,
__int64 Value
);
__int64 _InterlockedExchange64_nf(
__int64 volatile * Target,
__int64 Value
);
__int64 _InterlockedExchange64_rel(
__int64 volatile * Target,
__int64 Value
);
Parameters
[in, out] Target
Pointer to the value to be exchanged. The function sets this variable to Value and returns its prior value.[in] Value
Value to be exchanged with the value pointed to by Target.
Return Value
Returns the initial value pointed to by Target.
Requirements
Intrinsic |
Architecture |
Header |
|---|---|---|
_InterlockedExchange, _InterlockedExchange8, _InterlockedExchange16, _InterlockedExchange64 |
x86, ARM, x64 |
<intrin.h> |
_InterlockedExchange_acq, _InterlockedExchange_nf, _InterlockedExchange_rel, _InterlockedExchange8_acq, _InterlockedExchange8_nf, _InterlockedExchange8_rel, _InterlockedExchange16_acq, _InterlockedExchange16_nf, _InterlockedExchange16_rel, _InterlockedExchange64_acq, _InterlockedExchange64_nf, _InterlockedExchange64_rel, |
ARM |
<intrin.h> |
_InterlockedExchange_HLEAcquire, _InterlockedExchange_HLERelease, _InterlockedExchange64_HLEAcquire, _InterlockedExchange64_HLERelease |
x86, x64 |
<immintrin.h> |
Remarks
_InterlockedExchange provides compiler intrinsic support for the Win32 Windows SDK InterlockedExchange function.
There are several variations on _InterlockedExchange that vary based on the data types they involve and whether processor-specific acquire or release semantics is used.
While the _InterlockedExchange function operates on 32-bit integer values, _InterlockedExchange8 operates on 8-bit integer values, _InterlockedExchange16 operates on 16-bit integer values, and _InterlockedExchange64 operates on 64-bit integer values.
On ARM platforms, use the intrinsics with _acq and _rel suffixes for acquire and release semantics, such as at the beginning and end of a critical section. The intrinsics with an _nf ("no fence") suffix do not act as a memory barrier.
On Intel platforms that support Hardware Lock Elision (HLE) instructions, the intrinsics with _HLEAcquire and _HLERelease suffixes include a hint to the processor that can accelerate performance by eliminating a lock write step in hardware. If these intrinsics are called on platforms that do not support HLE, the hint is ignored.
These routines are only available as intrinsics.
Example
For a sample of how to use _InterlockedExchange, see _InterlockedDecrement.