[#BloombergLP-bsls-AtomicOperations_ALL_ALL_ClangIntrinsics-testAndSwapInt64]
= xref:BloombergLP.adoc[BloombergLP]::xref:BloombergLP/bsls.adoc[bsls]::xref:BloombergLP/bsls/AtomicOperations_ALL_ALL_ClangIntrinsics.adoc[AtomicOperations_ALL_ALL_ClangIntrinsics]::testAndSwapInt64
:relfileprefix: ../../../
:mrdocs:

Conditionally swap `atomicInt` with sequential consistency.

== Synopsis

Declared in `<bsls_atomicoperations_all_all_clangintrinsics.h>`

[source,cpp,subs="verbatim,replacements,macros,-callouts"]
----
static
xref:BloombergLP/bsls/Types/Int64.adoc[Types::Int64]
testAndSwapInt64(
    xref:BloombergLP/bsls/Atomic_TypeTraits-0b/Int64.adoc[AtomicTypes::Int64]* atomicInt,
    xref:BloombergLP/bsls/Types/Int64.adoc[Types::Int64] compareValue,
    xref:BloombergLP/bsls/Types/Int64.adoc[Types::Int64] swapValue);
----

== Description

Conditionally set the value of the specified `atomicInt` to the specified `swapValue` if and only if the value of `atomicInt` equals the value of the specified `compareValue`, and return the initial value of `atomicInt`, providing the sequential consistency memory ordering guarantee. The whole operation is performed atomically.

== Return Value

initial value of `atomicInt` before the operation

== Parameters

[cols="1,4"]
|===
| Name| Description
| *atomicInt*
| atomic 64‐bit integer to test and possibly update
| *compareValue*
| expected current value of `atomicInt`
| *swapValue*
| value to store if the comparison succeeds
|===


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