shmwrite.c~

这个资料非常不错

/* Includes */
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/shm.h>

typedef struct
{
int tc_number;
char ap_name[5];
char mymessage[20];

} COMM_TABLE;

main()
{

/* local variables */
int ret= 0;
key_t key;
int i;
int shm_id;
int found = 0;
COMM_TABLE *comm_reg;

key = ftok(".",'w');

/* create a share memory if not exist */
if ((shm_id = shmget(key ,sizeof(COMM_TABLE),IPC_CREAT|IPC_EXCL|0666)) == -1)
{
/* share memory has been created */
if ((shm_id = shmget(key , sizeof(COMM_TABLE),0)) == -1)
{
printf("error = %d\n", errno);
return (ret);

}
}
comm_reg = (COMM_TABLE *) shmat(shm_id, (char *) 0, (int)NULL);
comm_reg->tc_number= 10000000;
}