Compiler directive

실행 시간 측정하기

#ifdef TIMES
	start = dclock();
#endif
	//시간 측정 부분
#ifdef TIMES
	end = dclock() - start();
    printf(end);
#endif

$gcc -DTIMES -o t1 t1.c

• -D
  • compiler directive 명령어
• TIMES
  • 임의로 이름 설정 가능함

 

#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <sys/time.h>

main() {
	int status;
	pid_t pid;
    
#ifdef TIMES
	struct timeval stime,etime;
	int time_result;
#endif

	pid = fork();
    
#ifdef TIMES
	gettimeofday(&stime, NULL);
#endif

	if (pid == 0) {
		printf("--> Child process\n");
		sleep(5);
		exit(3);
	}

	printf("--> Parent process\n");

	while (waitpid(pid, &status, WNOHANG) == 0) {
		printf("Parent still wait..\n");
		sleep(1);
	}
	printf("Child Exit Status : %d\n", status>>8);

#ifdef TIMES
        gettimeofday(&etime, NULL);
        time_result = etime.tv_usec - stime.tv_usec;
        printf("TIMES == %ld %ld %ld\n", etime.tv_usec, stime.tv_usec, time_result);
#endif

}