/*ARGSUSED*/
int openmem(int trystart)
{
initpkey();
shmid = shmget(pkey, SHMFLAG, 0);
if (shmid < 0) { /* Could not find the shared memory */
if (errno != ENOENT) { /* Error other not created yet */
perror("shmget");
exit(1);
}
if (trystart==1){ /* Create the memory */
startdaemon();
}
else if (trystart < 0){ /* Just checking if it exists */
return 0;
}
else { /* Wanted to use it, but... */
fprintf(stderr,"Warning: Daemon not running!\n");
exit(1);
}
shmid = shmget(pkey, SHMFLAG, 0);
if (shmid < 0) { /* This is a bummer of an error */
ERROR(1, ("Daemon not running (err:%d)\n",errno));
exit(1);
}
}
sharedMemory = (struct memory *) shmat(shmid, 0, 0);
if (sharedMemory == (struct memory *) -1) {
printf("Error number: %d\n",errno);
perror("shared memory");
exit(1);
}
setup_memory(sharedMemory);
opensem();
return 1;
}
int main()
{
int semid, shmid;
char *shmaddr;
if ((shmid = createshm(".", 'm', SHM_SIZE)) == -1){
exit (1);
}
if((shmaddr = shmat (shmid, (char *)0, 0)) == (char *)-1){
perror ("attach shared memory error!\n");
exit (1);
}
if((semid = opensem("." ,'s')) == -1){
exit (1);
}
while(1){
printf("reader: ");
sem_p(semid,0); /* P操作 */
printf("%s", shmaddr);
sem_v(semid,0); /* V操作 */
}
}
int main()
{
int semid,shmid;
char *shmaddr=NULL;
if((shmid=createshm(".",'m',SHM_SIZE))==-1)
{
exit(1);
}
if((shmaddr=shmat(shmid,(char*)0,0))==(char *)-1)
{
perror("attach shared memory error\n");
exit(1);
}
if((semid=opensem(".",'s'))==-1)
{
exit(1);
}
while(1)
{
waitsem(semid,0);
p(semid,0);
printf("reader:");
printf("%s\n",shmaddr);
my_sleep(5);
v(semid,0);
// my_sleep(5);
}
}
