管道__2018.07.30

代码1：

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>

int main()
{
    int res=mkfifo("my_fifo",0777);
    if(res==0)
    {
        printf("FIFO created\n");
    }
    exit(EXIT_SUCCESS);
}

代码2：

#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <fcntl.h>
#include <sys/types.h>
#include <sys/stat.h>

#define FIFO_NAME "Mcfifo"

int main(int argc,char *argv[])
{
    int res;
    int open_mode=0;
    int i;
     if(argc<2)
     {
        fprintf(stderr,"Usage:%s <some combination of: O_RDONLY O_WRONLY O_WRONLY O_NONBLOCK>\n",*argv);
        exit(EXIT_FAILURE);
     }
     for(i=1;i<argc;i++)
     {
        if(strncmp(*++argv,"O_RDONLY",8)==0)
        {
            open_mode |= O_RDONLY;
        }
        if(strncmp(*argv,"O_WRONLY",8)==0)
        {
            open_mode |= O_WRONLY;
        }
        if(strncmp(*argv,"O_NONBLOCK",10)==0)
        {
            open_mode |= O_NONBLOCK;
        }
     }
     if(access(FIFO_NAME,F_OK)==-1)
     {
        res=mkfifo(FIFO_NAME,07777);
        if(res!=0)
        {
            fprintf(stderr,"Could not create fifo %s\n",FIFO_NAME);
            exit(EXIT_FAILURE);
        }
     }

     printf("Process %d opening FIFO\n",getpid());
     res=open(FIFO_NAME,open_mode);
     printf("Process %d result %d\n",getpid());
     sleep(5);
     if(res!=-1)
     {
        (void)close(res);
     }
     printf("Process %d finished\n",getpid());
     exit(EXIT_FAILURE);
}