为什么std :: atomic_thread_fence具有“ C”链接？
[英]Why does std::atomic_thread_fence have “C” linkage?
问题描述
我不知道为什么希望此功能具有“ C”而不是“ C ++”链接。
2 个解决方案
解决方案1
5 2017-02-01 21:24:45
That was added by LWG issue 1479 which was addressing a last-minute comment on C++11. 
LWG问题1479在解决有关C ++ 11的最新评论时对此进行了补充。
The rationale for this change was C language compatibility (C11 thread library has identically-named function atomic_thread_fence in stdatomic.h). 进行此更改的理由是C语言兼容（C11线程库在stdatomic.h中具有相同名称的函数atomic_thread_fence ）。
As far as I understand, it was always a plan that C and C++ atomic libraries can coexist: other examples of compatiblity are the C-compatible type aliases for std::atomic, such as atomic_int and the C-compatibility macro ATOMIC_VAR_INIT 据我了解，C和C ++原子库始终可以共存是一个计划：兼容性的其他示例是std :: atomic的C兼容类型别名，例如atomic_int和C兼容性宏ATOMIC_VAR_INIT
解决方案2
0 2017-02-01 15:51:18
atomic_thread_fence establishes memory synchronization ordering of non-atomic and relaxed atomic accesses. atomic_thread_fence建立非原子访问和宽松原子访问的内存同步顺序。
Concurrency, especially relaxed-memory concurrency, is a notoriously subtle and error-prone domain, and so verifying such optimisations is of great interest. 并发，尤其是宽松的内存并发，是一个众所周知的微妙且容易出错的领域，因此验证这种优化非常令人感兴趣。 Ref1 . 参考1 。
For such thing is widely used CompCertTSO . 为此， CompCertTSO被广泛使用。
CompCertTSO is a compiler that generates x86 assembly code from ClightTSO, a large subset of the C programming language enhanced with concurrency primitives for thread management and synchronisation, and with a TSO relaxed memory model based on the x86-TSO model. CompCertTSO是从ClightTSO生成x86汇编代码的编译器，ClightTSO是C编程语言的大子集，并增强了用于线程管理和同步的并发原语，以及基于x86-TSO模型的TSO宽松内存模型。
So, for verification, optimisation and testing purposes is desirable for this function to have "C" linkage. 因此，出于验证，优化和测试的目的，希望此功能具有“ C”链接。
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