pipe_1.c

工ARM＿LINUX的几个源代码

#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);
              			 }
       		 }
}