Cannot access ifreq structure definition, __USE_MISC macro undefined - c

Question

I am trying to compile the following single C file (called main.c):
#include <stdio.h>
#define __USE_MISC 1
#include <net/if.h>
int main(int argc, char **argv)
{
ifreq id_ifreq;
fprintf(stdout, ">>>>>> OK <<<<<<\n");
}
... using "gcc main.c -o main". I get the following error:
main.c: In function ‘main’:
main.c:9:2: error: unknown type name ‘ifreq’
I know that "ifreq" structure definition lies within a "#ifdef __USE_MISC" macro, however, I cannot activate that block of code.
I developed the following code for checking which MACROS are defined (compiled with "gcc main.c -o main"):
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <net/if.h>
int main(int argc, char **argv)
{
#ifdef __USE_MISC
printf("__USE_MISC defined\n");
#endif
#ifdef _GNU_SOURCE
printf("_GNU_SOURCE defined\n");
#endif
#ifdef _BSD_SOURCE
printf("_BSD_SOURCE defined\n");
#endif
#ifdef _SVID_SOURCE
printf("_SVID_SOURCE defined\n");
#endif
}
The result is that they are all defined but the "_GNU_SOURCE" one. However, I am still not capable of using the definition of the "ifreq" structure included in the "net/if.h" file.
Anybody can help?

Answer 1

You are omitting the struct keyword (in C, a struct definition is not a typedef)
#include <stdio.h>
#include <net/if.h>
int main(int argc, char **argv)
{
struct ifreq id_ifreq;
fprintf(stdout, ">>>>>> OK <<<<<<\n");
return 0;
}