如何获取 printf 风格的编译时警告或错误-C/C++问题

How to get printf style compile-time warnings or errors(如何获取 printf 风格的编译时警告或错误)

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问题描述

我想编写一个类似 printf 的例程，但不是在功能方面，而是我希望该例程与 printf 具有相同的编译检查特性.

I would like to write a routine like printf, not functionally-wise, but rather I'd like the routine to have the same time compile check characteristics as printf.

例如，如果我有:

{
   int i;
   std::string s;
   printf("%d %d",i);
   printf("%d",s.c_str());
}

编译器会这样抱怨:

1 cc1plus: warnings being treated as errors
2 In function 'int main()':
3 Line 8: warning: too few arguments for format
4 Line 9: warning: format '%d' expects type 'int', but argument 2 has type 'const char*'

代码示例

printf 和 co 是编译器区别对待的特殊函数，还是有一些技巧可以让它在任何用户定义的函数上工作?我感兴趣的具体编译器是 gcc 和 msvc

Are printf and co special functions that the compiler treats differently or is there some trick to getting this to work on any user defined function? The specific compilers I'm interested in are gcc and msvc

推荐答案

不同的编译器可能会以不同的方式实现此功能.在 GCC 中，它是通过带有 format 属性的 __attribute__ 说明符实现的(阅读它这里).编译器执行检查的原因只是在 GCC 提供的标准头文件中，printf 函数是用 __attribute__((format(printf, 1, 2)))


Different compilers might implement this functionality differently. In GCC it is implemented through __attribute__ specifier with format attribute (read about it here). The reason why the compiler performs the checking is just that in the standard header files supplied with GCC the printf function is declared with __attribute__((format(printf, 1, 2)))
以完全相同的方式，您可以使用 format 属性将相同的格式检查功能扩展到您自己的可变参数函数，这些函数使用与 printf 相同的格式说明符.
In exactly the same way you can use format attribute to extend the same format-checking functionality to your own variadic functions that use the same format specifiers as printf.
只有当您使用的参数传递约定和格式说明符与标准 printf 和 scanf 函数使用的相同时，这一切才会起作用.检查被硬编码到编译器中.如果您对可变参数传递使用不同的约定，编译器将不会帮助您检查它.
This all will only work if the parameter passing convention and the format specifiers you use are the same as the ones used by the standard printf and scanf functions. The checks are hardcoded into the compiler. If you are using a different convention for variadic argument passing, the compiler will not help you to check it.

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