shm_1.c

Linux大学上机源码学习

#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>
#include <stdio.h>
#define SHMSZ 27
int main(void)
{ char c;
  int shmid;
  key_t key;
  char * shm,*s;
  /*create a share_memory named 5678*/
  key=5678;
  if((shmid=shmget(key,SHMSZ,IPC_CREAT|0666))<0)
    exit(0);
 /* connecting this share_memory to this process */
  if ((shm=shmat(shmid,NULL,0))==NULL)
    exit(0);
/* writting some letters to this memory for other  process */
  s=shm;
  for(c='a';c<='z';c++)
    *s++=c;
  *s='#';
/* waitting for another process change this memory */
  while( *shm !='*')
     sleep(1);
  exit(0);
}