有宏返回一个值 [英] Have macro 'return' a value

问题描述

我使用的宏，我认为它可以正常工作 -

I'm using a macro and I think it works fine -

#define CStrNullLastNL(str) {char* nl=strrchr(str,'\n'); if(nl){*nl=0;}}

所以它的作用是清除一个字符串中的最后一个换行符，

So it works to zero out the last newline in a string, really its used to chop off the linebreak when it gets left on by fgets.

因此，我想知道我是否可以从宏中返回一个值，所以它可以是叫做

So, I'm wondering if I can "return" a value from the macro, so it can be called like

func( CStrNullLastNL( cstr ) ) ;

或者我必须写一个函数

推荐答案

对于要返回值的宏，宏本身必须是一个表达式。

For a macro to "return a value", the macro itself has to be an expression. Your macro is a statement block, which cannot evaluate to an expression.

你真的应该写一个 inline 函数。它将会一样快速和更可维护。

You really ought to write an inline function. It will be just as fast and far more maintainable.

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