MSVC的errno线程安全 [英] MSVC errno thread safety

问题描述

是错误号上MSVC线程安全的？

Is errno on MSVC thread-safe?

根据这个问题 POSIX要求错误号是线程安全的。但是MSVC大概POSIX不兼容和 MSDN 不告诉线程安全的东西。 MSDN矛盾提到错误号声明为的extern INT错误号; ，又可作为的#define错误号（* _errno（））

According to the answers in this question POSIX requires that errno is thread-safe. But MSVC is probably not POSIX compliant and MSDN does not tell anything about thread-safety. MSDN contradictory mentions that errno is declared as extern int errno;, but also as #define errno (*_errno())

推荐答案

虽然MSVC绝对不是POSIX兼容，错误号在MSVC运行时实现（至少为MSVC2008）的线程安全的方式。

Although MSVC is definitely not POSIX compliant, errno is implemented in the MSVC runtime (at least as of MSVC2008) in a threadsafe manner.

虽然文档指出这是的extern INT错误号它是作为一个的#define 实际实现的一个功能，允许线程安全的罚款。如果你通过反汇编窗口此功能一步到位，很显然，线程本地存储被使用。

Although the documentation states that it is extern int errno it's actually implemented as a #define to a function which allows thread-safety to be imposed. If you step through this function in the disassembly window, it is clear that thread local storage is used.

不幸的是，我不能指向证实了这一点任何正式文件，但生活就是这样！

Sadly I can't point to any official documentation that confirms this but such is life!

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