pipe_lock.c

Linux大学上机源码学习

#include <limits.h>
#include <signal.h>
#include <unistd.h>
#include <stdio.h>
#include <string.h>
#include <sys/file.h>
int p1,p2;
main()
{ 
 int fd[2],r,k=0,n;
 char outp[100],inp[4096],outpx[100],c;
 pipe(fd);
 printf("x=%ld,%d\n",F_LOCK,F_ULOCK);
 sleep(5);
 while((p1=fork())==-1);
 if (p1==0)
  {
  close(fd[0]);
  lockf(fd[1],F_LOCK,0);
   k=1;
   while(k<=3)
     {sprintf(outpx,"c1:%d",k);
     write(fd[1],outpx,strlen(outpx));
     sleep(1); 
     k++;
     }
    write(fd[1],":end",4);  
   lockf(fd[1],F_ULOCK,0);
   exit(0);
  }
 else
    { 
     while((p2=fork())==-1);
     if(p2==0)
       { k=1;
        close(fd[0]);
        lockf(fd[1],F_LOCK,0); 
        while(k<=2)
          { sprintf(outpx,"c2:%d",k);
            write(fd[1],outpx,strlen(outpx));   
            k++;
          }
        lockf(fd[1],F_ULOCK,0);
        exit(0);
        }
     
      else
        {wait(0);
         wait(0);      
         n=read(fd[0],inp,4096);
         printf("rectoatl=%d,recstring=%s",n,inp);
	 }
    }
}