展开引号字符串内的宏 [英] Expand macros inside quoted string

问题描述

可能重复：结果
   C宏创建的字符串

我有一个接受的类型的char * 的一个参数，比如 F A功能（字符串）; 结果
如果字符串参数是通过即时函数调用定义，怎么能宏在字符串体内扩大呢？

I have a function which accepts one argument of type char*, like f("string");
If the string argument is defined by-the-fly in the function call, how can macros be expanded within the string body?

例如：

#define COLOR #00ff00
f("abc COLOR");

将相当于

f("abc #00ff00");

而是不进行扩张，而且功能字面上接收 ABC COLOR 。

在我特别需要扩大宏观准确 \\＃00FF00 \\，使这一报价令牌与传递给字符串参数的其余部分连接起来 F（），报价包括在内;也就是说，preprocessor必须完成他的工作，并欢迎编译器将来自的code F（ABC COLOR）; 到 F（ABC \\＃00FF00 \\）;

In particular, I need to expand the macro to exactly \"#00ff00\", so that this quoted token is concatenated with the rest of the string argument passed to f(), quotes included; that is, the preprocessor has to finish his job and welcome the compiler transforming the code from f("abc COLOR"); to f("abc \"#00ff00\"");

推荐答案

您不能展开在字符串中宏，但你可以写

You can't expand macros in strings, but you can write

#define COLOR "#00ff00"

f("abc "COLOR);

请记住，这级联是由C preprocessor做的，仅仅是简单的拼接字符串，而不是变量左右的功能。

Remember that this concatenation is done by the C preprocessor, and is only a feature to concatenate plain strings, not variables or so.

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