sigsend.c

linux父子进程间关系

#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#define M  4
#define MAX  100

int main(int argc, char** argv)
{
    int fd0;
    int success,count;
    char s[M];
    if (argc < 2) {
        printf("USEAGE: sigsend PID \n");
        exit(0);
    }
    int ipid;
    ipid = atoi(argv[1]);
    if (ipid <= 0 ) 
    {
        printf("pid error!\n");
        exit(1);
    }
    kill(ipid, SIGUSR2);
    printf("Send SIGUSR2\n");
    //sleep(5);

    while ((fd0 = open("test.txt", O_RDONLY)) < 0)
         {
             if(errno==ENOENT)
             {
                 sleep(1);
                 continue;
             }
             write(1, "open fifo file Error!\n",sizeof("open file Error!\n"));
             exit(1);
         }
    count=0;
    while(count<=MAX)
    {
        success=read(fd0,s,M);
        success=write(1,s,success);
        count=count+success;
        if(success<=0)
            break;
    }
    kill(ipid,SIGUSR1);
    printf("\nSend SIGUSR1\n");
    unlink("test.txt");
    return 0;
}