POSIX compliant program that prints the POSIX defined configuration options supported on any given system using feature test macros

#define _POSIX_SOURCE
#define _POSIX_C_SOURCE 199309L
#include<stdio.h>
#include<unistd.h>
int main()
{
#ifdef _POSIX_JOB_CONTROL
printf("System supports job control\n");
#else
printf("System does not support job control \n");
#endif
#ifdef _POSIX_SAVED_IDS
printf("System supports saved set-UID and saved set-GID\n");
#else
printf("System does not support saved set-UID and saved set-GID \n");
#endif
#ifdef _POSIX_CHOWN_RESTRICTED
printf("chown_restricted option is %d\n”,
_POSIX_CHOWN_RESTRICTED);
#else
printf("System does not support chown_restricted option \n");
#endif
#ifdef _POSIX_NO_TRUNC
printf("Pathname trunc option is %d\n",_POSIX_NO_TRUNC);
#else
printf("System does not support system-wide pathname trunc option \n");
#endif
#ifdef _POSIX_VDISABLE
printf("Disable character for terminal files is %d\n",
_POSIX_VDISABLE);
#else
printf(" System does not support _POSIX_VDISABLE \n");
#endif
return 0;
}

Output
System supports job control
System supports saved set-UID and saved set-GID
chown_restricted option is 1
Path name trunc option is 1
Disable character for terminal files is 0