Linux 使用信号分别在两个进程中打印AAA和BBB

#include "sys/types.h"
#include "unistd.h"
#include "signal.h"

pid_t pid;

void sigusr1_handler(int n)
{
	if(pid > 0)
		printf("AAAA\n");
	else if(pid == 0)
		printf("BBBB\n");
}

void sigalrm_handler(int n)
{
	static int turn = 0;
	if(turn == 0)
		raise(SIGUSR1);
	else
		kill(pid, SIGUSR1);

	turn = (turn+1)%2;
}

int main()
{
	signal(SIGUSR1, sigusr1_handler);

	pid = fork();
	if(pid == 0)
	{
		while(1)
			pause();
	}
	else if(pid > 0)
	{
		signal(SIGALRM, sigalrm_handler);
		while(1)
		{
			alarm(1);
			pause();
		}
	}

	return 0;
}

先放着。。以后补充自己关于信号知识的理解