c - 在 C 中调用函数而不是宏

Question

我的问题是:如果你有一个宏和一个同名的函数，那么只会调用宏，对吗？如果我想调用函数而不是宏怎么办？

Answer 1

如果你有一个函数和一个类似函数的宏，它们都命名为 foo 并且想要调用函数版本，你可以这样做:

(foo)(args)

这是有效的，因为类似函数的宏名称必须后跟带括号的参数列表才能进行替换。

这在 ISO C99 标准的第 7.1.4/1 节中提到:

Any function declared in a header may be additionally implemented as a function-like macro defined in the header, so if a library function is declared explicitly when its header is included, one of the techniques shown below can be used to ensure the declaration is not affected by such a macro. Any macro definition of a function can be suppressed locally by enclosing the name of the function in parentheses, because the name is then not followed by the left parenthesis that indicates expansion of a macro function name. For the same syntactic reason, it is permitted to take the address of a library function even if it is also defined as a macro. The use of #undef to remove any macro definition will also ensure that an actual function is referred to.

但是，如果您需要这样做，您可能应该在代码中添加注释来解释它，因为它看起来有点奇怪并且不常见。如果可行，重命名函数以避免名称冲突从长远来看可能更易于维护。