C++犄角旮旯之宏函数作为参数

宏函数可作为另一个宏函数的参数。见下面的例子代码。

//testmacro.cpp#define DECLARE_ELEMENT(type, value, commit)\type = value,#define DECLARE_COMMON_ELEMENTS(F)\F(TYINT32, 0, int)\F(TYCHAR, 1, char)enum BASE_TYPE{DECLARE_COMMON_ELEMENTS(DECLARE_ELEMENT)};int main(){BASE_TYPE t1 = TYINT32;BASE_TYPE t2 = TYCHAR;return 0;}

预编译头文件

g++ -E testmacro.cpp -o pre.h

预编译结果

# 1 "testmacro.cpp"# 1 "<command-line>"# 1 "/usr/include/stdc-predef.h" 1 3 4# 1 "<command-line>" 2# 1 "testmacro.cpp"# 9 "testmacro.cpp"enum BASE_TYPE{ TYINT32 = 0, TYCHAR = 1,};int main(){ BASE_TYPE t1 = TYINT32; BASE_TYPE t2 = TYCHAR; return 0;}