atomic_fetch_key.adoc

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atomic_fetch_key

Atomically replace the value pointed to by object with the result of the computation.

C atomic_fetch_key(volatile A *object,
                   M operand)

C atomic_fetch_key_explicit(volatile A *object,
                            M operand,
                            memory_order order)

C atomic_fetch_key_explicit(volatile A *object,
                            M operand,
                            memory_order order,
                            memory_scope scope)

Parameters

object

order

scope

operand

See the table below.

Description

These operations perform arithmetic and bitwise computations. All of these operations are applicable to an object of any atomic integer type. The key, operator, and computation correspondence is given in the table below:

key	op	computation
add	+	addition
sub	-	subtraction
or	|	bitwise inclusive or
xor	^	bitwise exclusive or
and	&	bitwise and
min	min	compute min
max	max	compute max

For atomic_fetch and modify functions with key = add or sub on atomic types atomic_intptr_t and atomic_uintptr_t, M is ptrdiff_t. For atomic_fetch and modify functions with key = or, xor, and, min and max on atomic types atomic_intptr_t and atomic_uintptr_t, M is intptr_t and uintptr_t.

Atomically replaces the value pointed to by object with the result of the computation applied to the value pointed to by object and the given operand. Memory is affected according to the value of order. These operations are atomic read-modify-write operations (as defined by section 5.1.2.4 of the C11 specification). For signed integer types, arithmetic is defined to use two’s complement representation with silent wrap-around on overflow; there are no undefined results. For address types, the result may be an undefined address, but the operations otherwise have no undefined behavior. Returns atomically, the value pointed to by object immediately before the effects.

atomicFunctionsInc.adoc

Also see

Atomic Functions

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