/*
 * shmstat.c
 * Gets statistics for a shared memory segment.
 */

#include <stdio.h>
#include <sys/shm.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <errno.h>
#include <string.h>
#include <time.h>

int main(int argc, char **argv)
{
	key_t key;
	int shm;
	struct shmid_ds shmstat;

	if((key=ftok("sharedmem",'a'))==-1)
	{
		fprintf(stdout,"failed to get key for shared memory segment %d, %s\n",errno,strerror(errno));
		fflush(stdout);
		return -1;
	}

	if((shm=shmget(key,0, S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | IPC_CREAT))==-1)
	{
		fprintf(stdout,"failed to allocate shared memory segment %d, %s\n",errno,strerror(errno));
		fflush(stdout);
		return -1;
	}

	if(shmctl(shm,IPC_STAT,&shmstat)==-1)
	{
		fprintf(stdout,"failed to destroy shared memory segment %d, %s\n",errno,strerror(errno));
		fflush(stdout);
		return -1;
	}
	fprintf(stdout,"shared memory segment stats:\n\tsize: %10d\n\tattached: %s\tdetached: %s\tchanged: %s\t#attached: %10d\n", shmstat.shm_segsz,ctime(&shmstat.shm_atime),ctime(&shmstat.shm_dtime),ctime(&shmstat.shm_ctime),(int)shmstat.shm_nattch);

	return 0;
}