一个消息队列例子，第一次运行正确，第二次运行就提示消息发送失败了
第一次运行还能正确发送消息，第二次运行就无法发出消息，请大家指点下，谢谢。
#include <sys/types.h>#include <sys/ipc.h>#include <sys/msg.h>#include <stdio.h>#include <stdlib.h>#include <string.h>int main(void){ key_t unique_key; int msgid; int status; char str1[] = {"test message:hello!"}; char str2[] = {"test message:goodbye!"}; struct msgbuf { long msgtype; char msgtext[1024]; }sndmsg,rcvmsg; if(msgid = msgget(IPC_PRIVATE, 0666) == -1) { printf("msgget error!\n"); exit(254); } sndmsg.msgtype = 111; sprintf(sndmsg.msgtext, "%s", str1); if(msgsnd(msgid, (struct msgbuf *)&sndmsg, sizeof(str1)+1, 0) == -1) { printf("msgtype 111 send error!\n"); exit(254); } if(status = msgrcv(msgid, (struct msgbuf *)&rcvmsg,80,111,IPC_NOWAIT) == -1) { printf("msgrcv error!\n"); exit(254); } printf("The received message:%s\n",rcvmsg.msgtext); msgctl(msgid, IPC_RMID, 0); exit(0);}