Phil
Phil
Programming language:Whatever
2021-08-15 23:33:22
0
Q:

variadic macros

matias
matias
Code: Whatever
2021-09-10 08:04:10 
// variadic_macros.cpp
#include <stdio.h>
#define EMPTY

#define CHECK1(x, ...) if (!(x)) { printf(__VA_ARGS__); }
#define CHECK2(x, ...) if ((x)) { printf(__VA_ARGS__); }
#define CHECK3(...) { printf(__VA_ARGS__); }
#define MACRO(s, ...) printf(s, __VA_ARGS__)

int main() {
    CHECK1(0, "here %s %s %s", "are", "some", "varargs1(1)\n");
    CHECK1(1, "here %s %s %s", "are", "some", "varargs1(2)\n");   // won't print

    CHECK2(0, "here %s %s %s", "are", "some", "varargs2(3)\n");   // won't print
    CHECK2(1, "here %s %s %s", "are", "some", "varargs2(4)\n");

    // always invokes printf in the macro
    CHECK3("here %s %s %s", "are", "some", "varargs3(5)\n");

    MACRO("hello, world\n");

    MACRO("error\n", EMPTY); // would cause error C2059, except VC++
                             // suppresses the trailing comma
}
1
piquet
piquet
Code: Whatever
2021-07-20 19:10:40 
#define eprintf(args…) fprintf (stderr, args)
0
TPain
TPain
Code: Whatever
2021-01-25 07:06:07 
#define eprintf(…) fprintf (stderr, __VA_ARGS__)
0

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