我应该从主返回EXIT_SUCCESS或0（）？ [英] Should I return EXIT_SUCCESS or 0 from main()?

问题描述

这是一个简单的问题，但我一直看到矛盾的答案：如果一个C ++程序返回主程序 0 或 EXIT_SUCCESS ？

It's a simple question, but I keep seeing conflicting answers: should the main routine of a C++ program return 0 or EXIT_SUCCESS?

#include <cstdlib>
int main(){return EXIT_SUCCESS;}

或

int main(){return 0;}

他们是同样的事情？应 EXIT_SUCCESS 只能用用于出口（）？

我觉得 EXIT_SUCCESS 将是一个更好的选择，因为其他软件可能要认为零故障，但我也听说，如果返回 0 ，编译器能够将其更改为不同的值反正。

I thought EXIT_SUCCESS would be a better option because other software may want to deem zero as failure, but I also heard that if you return 0, the compiler is capable of changing it to a different value anyway.

推荐答案

EXIT_FAILURE ，无论是在return语句主或作为参数传递给退出（），也是唯一可移植的方法来指示在C或C ++程序失败。 退出（1）实际上可以在信号VMS成功的终止，例如。

EXIT_FAILURE, either in a return statement in main or as an argument to exit(), is the only portable way to indicate failure in a C or C++ program. exit(1) can actually signal successful termination on VMS, for example.

如果你打算使用 EXIT_FAILURE 当你的程序出现故障，那么你还不如用 EXIT_SUCCESS 当它成功了，只是为了对称的缘故。

If you're going to be using EXIT_FAILURE when your program fails, then you might as well use EXIT_SUCCESS when it succeeds, just for the sake of symmetry.

在另一方面，如果程序永远信号故障，您可以使用 0 或 EXIT_SUCCESS 。两者都通过标准保证表示成功完成。 （这是几乎没有可能的， EXIT_SUCCESS 可能比0的值，但它等于0每次我听过的执行情况。）

On the other hand, if the program never signals failure, you can use either 0 or EXIT_SUCCESS. Both are guaranteed by the standard to signal successful completion. (It's barely possible that EXIT_SUCCESS could have a value other than 0, but it's equal to 0 on every implementation I've ever heard of.)

使用 0 有轻微好处是你不需要的#include＆LT;＆stdlib.h中GT; 中C，或的#include＆LT; cstdlib＆GT; 在C ++中（如果您使用的是收益语句，而不是调用退出（）） - 但你会被直接或间接反正包括STDLIB任何显著大小的程序

Using 0 has the minor advantage that you don't need #include <stdlib.h> in C, or #include <cstdlib> in C++ (if you're using a return statement rather than calling exit()) -- but for a program of any significant size you're going to be including stdlib directly or indirectly anyway.

对于这个问题，在C开始与1999年的标准，而在C ++中的所有版本，达到年底的main（）执行一个隐含的返回0; 无论如何，所以你可能不需要为使用 0 或 EXIT_SUCCESS 明确。 （但至少在C，我认为一个明确的 0的回报。来得到更好的风格）

For that matter, in C starting with the 1999 standard, and in all versions of C++, reaching the end of main() does an implicit return 0; anyway, so you might not need to use either 0 or EXIT_SUCCESS explicitly. (But at least in C, I consider an explicit return 0; to be better style.)

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