#ifdef CHECK_VARIABLE_EXISTS
extern int CHECK_VARIABLE_EXISTS;
#ifdef __CLASSIC_C__
int main(){
int ac;
char*av[];
#else
int main(int ac, char*av[]){
#endif
if(ac > 1000){return *av[0];}
return CHECK_VARIABLE_EXISTS;
}
#else /* CHECK_VARIABLE_EXISTS */
# error "CHECK_VARIABLE_EXISTS has to specify the variable"
#endif /* CHECK_VARIABLE_EXISTS */