-pthread标志在编译时的意义 [英] Significance of -pthread flag when compiling

问题描述

在各种多线程C和C ++项目中，我已经看到-pthread标志同时应用于编译和链接阶段，而其他人根本不使用它，而只是将-lpthread传递到链接阶段.

In various multi threaded C and C++ projects I've seen the -pthread flag applied to both the compiling and linking stage while others don't use it at all and just pass -lpthread to the linking stage.

不编译和链接-pthread标志是否存在任何危险-即-pthread的实际作用是什么?我主要对Linux平台感兴趣.

Is there any danger not compiling and linking with the -pthread flag - i.e. what does -pthread actually do ? I'm primarily interested in Linux platforms.

推荐答案

尝试:

gcc -dumpspecs | grep pthread

，然后查找以%{pthread:开头的任何内容.

and look for anything that starts with %{pthread:.

在我的计算机上，这导致文件使用-D_REENTRANT进行编译并与-lpthread链接.在其他平台上，这可能有所不同.使用-pthread具有最大的可移植性.

On my computer, this causes files to be compiled with -D_REENTRANT, and linked with -lpthread. On other platforms, this could differ. Use -pthread for most portability.

在GNU libc上使用_REENTRANT会更改某些libc标头的工作方式.作为一个具体示例，它使errno调用返回线程本地位置的函数.

Using _REENTRANT, on GNU libc, changes the way some libc headers work. As a specific example, it makes errno call a function returning a thread-local location.

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