blocks|key|1125791|text|您需要的是一个变量宏，它可以接受任意数量的参数。语法是#define+MACRO(fixedarg1,+fixedarg2,+...)。在宏的正文中，只需使用__VA_ARGS__引用所有变量参数。|type|unstyled|depth|inlineStyleRanges|offset|length|style|BOLD|CODE|entityRanges|data|1125792|不幸的是，您不能使最后一个arg返回类型，因为您必须统一处理整个变量块，它们必须是最后一个。但是，您可以很容易地将第二个arg设置为返回类型：|1125793|#define+MAKE_FUNCTION_TYPE(name,+ret,+...)+typedef+ret+(*name)(__VA_ARGS__)

MAKE_FUNCTION_TYPE(v_i,+int);
MAKE_FUNCTION_TYPE(i_v,+void,+int);
MAKE_FUNCTION_TYPE(ii_cp,+char+*,+int,+int);|code-block|syntax|javascript|1125794|这相当于|1125795|typedef+int+(*v_i)();
typedef+void+(*i_v)(int);
typedef+char+*+(*ii_cp)(int,+int);|1125796|您可以使用cc+-E进行检查。|1125797|entityMap^0|7|3|R|14|27|B|0|0|0|0|0|5|5|0^^$0|@$1|2|3|4|5|6|7|V|8|@$9|W|A|X|B|C]|$9|Y|A|Z|B|D]|$9|10|A|11|B|D]]|E|@]|F|$]]|$1|G|3|H|5|6|7|12|8|@]|E|@]|F|$]]|$1|I|3|J|5|K|7|13|8|@]|E|@]|F|$L|M]]|$1|N|3|O|5|6|7|14|8|@]|E|@]|F|$]]|$1|P|3|Q|5|K|7|15|8|@]|E|@]|F|$L|M]]|$1|R|3|S|5|6|7|16|8|@$9|17|A|18|B|D]]|E|@]|F|$]]|$1|T|3|-4|5|6|7|19|8|@]|E|@]|F|$]]]|U|$]]

What you want is a variadic macro, which can take an arbitrary number of arguments. The syntax is <code>#define MACRO(fixedarg1, fixedarg2, ...)</code>. In the body of the macro, you simply use <code>__VA_ARGS__</code> to refer to all of the variable arguments.

Unfortunately, you can't make the last arg the return type, because you have to treat the entire block of variable arguments uniformly and they must come last. However, you can make the second arg the return type very easily:

<pre><code>#define MAKE_FUNCTION_TYPE(name, ret, ...) typedef ret (*name)(__VA_ARGS__)

MAKE_FUNCTION_TYPE(v_i, int);
MAKE_FUNCTION_TYPE(i_v, void, int);
MAKE_FUNCTION_TYPE(ii_cp, char *, int, int);
</code></pre>

This is equivalent to

<pre><code>typedef int (*v_i)();
typedef void (*i_v)(int);
typedef char * (*ii_cp)(int, int);
</code></pre>

which you can check using <code>cc -E</code>.

blocks|key|1969197|text|如果您真的希望返回类型是最后一个，这是很复杂的，但是Boost.Preprocessor+(它同时适用于C和C%2B%2B)可以帮助实现它：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1969198|#include+<boost/preprocessor/tuple.hpp>
#include+<boost/preprocessor/variadic.hpp>
#include+<boost/preprocessor/control/if.hpp>
#include+<boost/preprocessor/comparison/greater.hpp>

#define+PP_VARIADIC_BACK(...)+\
++BOOST_PP_TUPLE_ELEM(BOOST_PP_DEC(BOOST_PP_VARIADIC_SIZE(__VA_ARGS__)),+\
++++BOOST_PP_VARIADIC_TO_TUPLE(__VA_ARGS__))
#define+PP_VARIADIC_POP_BACK(...)+\
++BOOST_PP_IF(BOOST_PP_GREATER(BOOST_PP_VARIADIC_SIZE(__VA_ARGS__),+1),+\
++++BOOST_PP_TUPLE_POP_BACK(BOOST_PP_VARIADIC_TO_TUPLE(__VA_ARGS__)),+\
++++(void))

#define+MAKE_FUNCTION_TYPE(name,+...)+\
++typedef+PP_VARIADIC_BACK(__VA_ARGS__)+(*name)+PP_VARIADIC_POP_BACK(__VA_ARGS__)|code-block|syntax|javascript|1969199|助手宏PP_VARIADIC_BACK至少需要一个参数并在最后一个参数中得到结果。助手宏PP_VARIADIC_POP_BACK至少需要一个参数。当它得到多个参数时，它会生成括号，其中包含除最后一个参数之外的所有参数的逗号分隔列表。当它得到一个参数时，它会产生文本(void)。|style|CODE|1969200|然后，这些就可以与typedef和(*name)部件放在一起了。由于您的示例使用的是在宏后面提供分号，所以最后一个分号被中断。|1969201|在coliru上的示例预处理器输出。|1969202|entityMap|0|LINK|mutability|MUTABLE|url|https://www.boost.org/doc/libs/1_71_0/libs/preprocessor/doc/index.html|1|http://coliru.stacked-crooked.com/a/f1d34f54d54778be^0|Q|I|0|0|0|3|G|18|K|3O|6|0|9|7|H|7|0|0|I|1|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@$A|11|B|12|1|13]]|C|$]]|$1|D|3|E|5|F|7|14|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|15|8|@$A|16|B|17|K|L]|$A|18|B|19|K|L]|$A|1A|B|1B|K|L]]|9|@]|C|$]]|$1|M|3|N|5|6|7|1C|8|@$A|1D|B|1E|K|L]|$A|1F|B|1G|K|L]]|9|@]|C|$]]|$1|O|3|P|5|6|7|1H|8|@]|9|@$A|1I|B|1J|1|1K]]|C|$]]|$1|Q|3|-4|5|6|7|1L|8|@]|9|@]|C|$]]]|R|$S|$5|T|U|V|C|$W|X]]|Y|$5|T|U|V|C|$W|Z]]]]

If you really want the return type last, that's complicated, but <a href="https://www.boost.org/doc/libs/1_71_0/libs/preprocessor/doc/index.html" rel="nofollow noreferrer">Boost.Preprocessor</a> (which works with both C and C++) can help do it:

<pre><code>#include &lt;boost/preprocessor/tuple.hpp&gt;
#include &lt;boost/preprocessor/variadic.hpp&gt;
#include &lt;boost/preprocessor/control/if.hpp&gt;
#include &lt;boost/preprocessor/comparison/greater.hpp&gt;

#define PP_VARIADIC_BACK(...) \
 BOOST_PP_TUPLE_ELEM(BOOST_PP_DEC(BOOST_PP_VARIADIC_SIZE(__VA_ARGS__)), \
 BOOST_PP_VARIADIC_TO_TUPLE(__VA_ARGS__))
#define PP_VARIADIC_POP_BACK(...) \
 BOOST_PP_IF(BOOST_PP_GREATER(BOOST_PP_VARIADIC_SIZE(__VA_ARGS__), 1), \
 BOOST_PP_TUPLE_POP_BACK(BOOST_PP_VARIADIC_TO_TUPLE(__VA_ARGS__)), \
 (void))

#define MAKE_FUNCTION_TYPE(name, ...) \
 typedef PP_VARIADIC_BACK(__VA_ARGS__) (*name) PP_VARIADIC_POP_BACK(__VA_ARGS__)
</code></pre>

The helper macro <code>PP_VARIADIC_BACK</code> requires at least one argument and results in the last argument. The helper macro <code>PP_VARIADIC_POP_BACK</code> requires at least one argument. When it gets more than one argument, it results in parentheses containing a comma-separated list of all arguments except the last one. When it gets exactly one argument, it results in the text <code>(void)</code>.

Then those can just be put together with the <code>typedef</code> and <code>(*name)</code> parts. The final semicolon is left off since your example uses provide a semicolon right after the macro.

<a href="http://coliru.stacked-crooked.com/a/f1d34f54d54778be" rel="nofollow noreferrer">Example preprocessor output on coliru.</a>

I want to take this:

<pre><code>typedef int (*PTR_FUN)(int);
typedef int (*PTR_FUN_FUN)(PTR_FUN, PTR_FUN);
</code></pre>

And define it like this:

<pre><code>MAKE_FUNCTION_TYPE(PTR_FUN, int, int);
MAKE_FUNCTION_TYPE(PTR_FUN_FUN, PTR_FUN, PTR_FUN, int);
</code></pre>

...where the number of arguments is dynamic, and the last argument is the return type.

If not possible to put the last arg as return type, then as the second arg.

How can I make a C macro for defining function typedefs?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我想要这个：typedef int (*PTR_FUN)(int);typedef int (*PTR_FUN_FUN)(PTR_FUN, PTR_FUN);并将其定义如下：MAKE_FUNCTION_TYPE(PTR_FUN, int, int);MAKE_FUNCTION_TYPE(PTR_FUN_FUN, PTR...

问如何制作C宏来定义函数类型？
EN

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问如何制作C宏来定义函数类型？EN