client.c

linux下面的文件锁和信号量的程序

#include "key.h"

int main (int argc,char ** argv){
	key_t key;
	int shmid;
	char * shmptr;
	COMM_TABLE * comm_reg;
	short count=1;
	
	key=ftok("~/tmp",1);
	/* get an existing share memory key */
	if((shmid=shmget(key,sizeof(COMM_TABLE),SHM_R))==-1){
		printf("shmget error\n");
		exit(1);
	}
	
	/* attach the share memory to address space of current progress */
	if((comm_reg=(COMM_TABLE *)shmat(shmid,0,SHM_R))==\
		(COMM_TABLE *)(-1)){
		printf("shmat error\n");
		exit(2);
	}
	printf("Share memory id is %d:\n",shmid);
	printf("share memory attached from %x to %x\n",\
				comm_reg,comm_reg+sizeof(COMM_TABLE));
	while(!comm_reg->is_available){
		printf("count %d\n",count);
		count++;
		sleep(1);
	}
	
	printf("message is %s \n",comm_reg->message);
	exit(0);
}
/* END OF FILE server.c */