#ifdef CHECK_FUNCTION_EXISTScharCHECK_FUNCTION_EXISTS();intmain(int ac,char*av[]){int ret =0;CHECK_FUNCTION_EXISTS();if(ac >100){
ret = *av[0];}return ret;}#else/* CHECK_FUNCTION_EXISTS */# error"CHECK_FUNCTION_EXISTS has to specify the function"#endif/* CHECK_FUNCTION_EXISTS */