__FILE__、__LINE__ 和 __FUNCTION__ 在 C++ 中的用法

2021-12-14 00:00:00 logging debugging c++ c-preprocessor

假设您的 C++ 编译器支持它们，是否有任何特殊原因不使用 __FILE__、__LINE__ 和 __FUNCTION__ 用于记录和调试目的?

Presuming that your C++ compiler supports them, is there any particular reason not to use __FILE__, __LINE__ and __FUNCTION__ for logging and debugging purposes?

我主要关心的是向用户提供误导性数据――例如，报告不正确的行号或由于优化而导致的函数――或因此导致性能下降.

I'm primarily concerned with giving the user misleading data―for example, reporting the incorrect line number or function as a result of optimization―or taking a performance hit as a result.

基本上，我可以相信 __FILE__、__LINE__ 和 __FUNCTION__ 会总是做正确的事吗?>

Basically, can I trust __FILE__, __LINE__ and __FUNCTION__ to always do the right thing?

推荐答案

__FUNCTION__ 是非标准的，__func__ 存在于 C99/C++11 中.其他的(__LINE__ 和 __FILE__)都很好.

__FUNCTION__ is non standard, __func__ exists in C99 / C++11. The others (__LINE__ and __FILE__) are just fine.

它总是会报告正确的文件和行(如果您选择使用 __FUNCTION__/__func__，则会报告正确的文件和行).优化是一个非因素，因为它是一个编译时宏扩展；它绝不会以任何方式影响性能.

It will always report the right file and line (and function if you choose to use __FUNCTION__/__func__). Optimization is a non-factor since it is a compile time macro expansion; it will never affect performance in any way.

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