jc.txt

进程的管道通信,可用来加强对进程通信的理解.

#include <unistd.h>
#include <signal.h>
#include <stdio.h>
int pid1,pid2;
main( )
    { 
int fd[2];
char outpipe[100],inpipe[100];
pipe(fd);                       /*创建一个管道*/
while ((pid1=fork( ))==-1);
if(pid1==0)
  {
lockf(fd[1],1,0);
    sprintf(outpipe,"child 1 process is sending message!"); 
	/*把串放入数组outpipe中*/
    write(fd[1],outpipe,50);     /*向管道写长为50字节的串*/
    sleep(5);                 /*自我阻塞5秒*/
    lockf(fd[1],0,0);
    exit(0);
            }
else
           {
while((pid2=fork( ))==-1);
    if(pid2==0)
{    lockf(fd[1],1,0);           /*互斥*/
           sprintf(outpipe,"child 2 process is sending message!");
           write(fd[1],outpipe,50);
           sleep(5);
           lockf(fd[1],0,0);
           exit(0);
        }
      else
        {  wait(0);              /*同步*/
           read(fd[0],inpipe,50);   /*从管道中读长为50字节的串*/
         printf("%s\n",inpipe);
         wait(0);
         read(fd[0],inpipe,50);
         printf("%s\n",inpipe);
         exit(0);
               }
        }
}