example29.c

LinuxNetProgramming Linux网络编程基础实例

#include	<stdlib.h>
#include	<sys/ipc.h>
#include	<sys/shm.h>

#define         SVSHM_MODE      (SHM_R | SHM_W | SHM_R >> 3 | SHM_R >> 6)

int
main(int argc, char ** argv)
{
	int			i, id;
	struct shmid_ds		buff;
	unsigned char		c, *ptr;
	
	if (argc != 2)
		printf("usage: shmread <pathname>");
	id = shmget(ftok(argv[1], 0), 0, SVSHM_MODE);
	ptr = shmat(id, NULL, 0);
	shmctl(id, IPC_STAT, &buff);
	for (i = 0; i < buff.shm_segsz; i++)
		if ( (c = *ptr++) != i)
			printf("ptr[%d] = %d", i, c);
	exit(0);
}