ser_c.c

Linux大学上机源码学习

#include <sem_op.h>
main()
{ 
struct exchange{
    char buf[BUFSIZ+80];
    int seq;
 }shm;
 int shmid;
 unsigned char *retval;
 int producer,consumer,i;
 consumer=open_semaphore_set(ftok("consumer",0),1);
 init_a_semaphore(consumer,0,1);
 producer=open_semaphore_set(ftok("producer",0),1);
 init_a_semaphore(producer,0,1);
 shmid=shmget(ftok("shared",0),sizeof(struct exchange),0666|IPC_CREAT);
 retval=shmat(shmid,(unsigned char *)0,0);
 for(i=0;;i++){
   printf("enter some text:");
   fgets(readbuf,BUFSIZE,stdin);
   semaphore_P(consumer);
   shm->seq=i;
   sprintf(shm->buf,"message %4d from producer%d is\"%s\"\n",i,getpif(),readbuf);
   semaphore_V(producer);
   if(strcmp(readbuf,"end",3)==0)
       break;
}
exit(0);
}