这是我的代码的一个较小的复制器:
#include <vector>
#include <iostream>
struct mystruct {
int a;
int param1;
int param2;
};
#define mycase 5, 5
#define mytest_1(test)
mystruct{ 1, test },
mystruct{ 2, test }
#define mytest_2(test)
mystruct{ 3, test },
mystruct{ 4, test }
#define mytest_all(test)
mytest_1(test),
mytest_2(test)
void check(std::vector<mystruct> a) {
for (int i = 0; i < a.size(); i++) {
std::cout << i << ": " << a[i].a << " " << a[i].param1 << " " << a[i].param2 << std::endl;
}
}
int main() {
check(std::vector<mystruct>{mytest_1(mycase), mytest_2(mycase)}); // works fine
check(std::vector<mystruct>{mytest_all(mycase)}); // doesn't work
return 0;
}
编译器产生以下错误(我使用的是g ++ 7.4.0(:
test.cpp:32:50: error: macro "mytest_1" passed 2 arguments, but takes just 1
check(std::vector<mystruct>{mytest_all(mycase)});
... ^
test.cpp:21:5: error: 'mytest_1' was not declared in this scope
mytest_1(test),
^
test.cpp:32:33: note: in expansion of macro 'mytest_all'
check(std::vector<mystruct>{mytest_all(mycase)});
^~~~~~~~~~
... # some more errors
据我从错误消息中了解,这是因为#define mycase 5, 5
由 1 个以上的参数组成,所以mytest_all
被展开成这样的东西:mytest_1(5, 5)
.
有没有办法以另一种方式定义mytest_all
以使其工作?考虑到我无法更改mytest_1
.谢谢!
这是解决方案:
#define IDENTITY(...) __VA_ARGS__
#define mytest_all(test)
mytest_1(IDENTITY(test)),
mytest_2(IDENTITY(test))
但是,如果您可以更改mytest_1
和2
,更好的选择是使它们使用...
/__VA_ARGS__
参数。