Macro fanciness for detecting disabled feature

if_not_disabled.c

#include <stdio.h>

#define STRINGIFY(X) "" #X
#define STRINGIFY2(X) STRINGIFY(X)

#define IF_NOT_DISABLED(ID, FN, ...) \
    (!strcmp("DISABLE_" #ID, STRINGIFY2(DISABLE_##ID))) ? FN(ID, ##__VA_ARGS__) : 0

enum my_enum {
    FOO,
    BAR,
    QUX
};

#define DISABLE_BAR

int func(enum my_enum id, char *name) {
    printf("Enum %s has value %d\n", name, id);
}

#define func_wrapper(id, name) IF_NOT_DISABLED(id, func, name)

int main(int argc, char **argv) {
    func_wrapper(FOO, "FOO");
    func_wrapper(BAR, "BAR"); // This line will be compiled out if -O3 enabled
    func_wrapper(QUX, "QUX");
}

//// OUTPUTS:
// > Enum FOO has value 0
// > Enum QUX has value 2