10-19.c

#include "sharemem.h"

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:");
		wait_sem(semid,0);
		sem_p(semid,0);

		printf("%s\n",shmaddr);
		sleep(10);

		sem_v(semid,0);
		sleep(10);
	}

	return 0;
}