消息队列工作机制 msgsnd: Invalid argument

msgsnd: Invalid argument

最近写个一个小程序 测试System V的消息队列工作机制，写完代码后编译通过但是运行出现这个错误msgsnd: Invalid argument
于是去Google ，可惜没有找到满意的结果，后来仔细检查代码发现 没有对消息类型赋值，花了我2个小时，终于搞定，以此告诫程序员要细心啊，呵呵

这是代码

/* 发送*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/msg.h>
#include <sys/ipc.h>


#define MAX_TEXT 512


struct my_msg_st
{
   long my_msg_type;   //消息类型
   char msg_text[MAX_TEXT];
};


int main(int argc,char ** argv)
{
int running = 1;
struct my_msg_st some_data;
int msgid;
char buffer[MAX_TEXT];

if( (msgid = msgget((key_t)12345,0666|IPC_CREAT) )== -1 )
{
   
    perror("msgget");
    exit(EXIT_FAILURE);
}
printf("msgid:%d\t\n",msgid);
while(running )
{
    printf("Enter the message to send:");
    fgets( buffer,MAX_TEXT,stdin);
   //some_data.my_msg_type =1;   //这一句为后来加上的,加上这一句就没有问题了
    strcpy(some_data.msg_text,buffer);

    if( msgsnd(msgid,(void*)&some_data,MAX_TEXT,IPC_NOWAIT) == -1 )
    {    
      perror("msgsnd");
      exit(EXIT_FAILURE);
    }
  
   if(strncmp(buffer,"end",3)==0)
   {
     running=0;
   }
}
return 0;
}

/*接收*/

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>
#include <sys/types.h>
#include <sys/msg.h>
#include <sys/ipc.h>

struct my_msg_st
{
   long my_msg_type;           //消息类型

   char msg_text[BUFSIZ];
};


int main(int argc,char ** argv)
{
int running = 1;
struct my_msg_st some_data;
int msgid;
int msg_to_receive =0;

if( (msgid = msgget((key_t)12345,0666|IPC_CREAT) )== -1 )
{

    perror("msgget");
    exit(EXIT_FAILURE);
}
printf("msgid:%d\t\n",msgid);
while(running )
{
   if( msgrcv(msgid,(void*)&some_data,BUFSIZ,msg_to_receive,0)==-1)
    {
      perror("msgrcv");
      exit(EXIT_FAILURE);
    }
    printf("receiver message:%s",some_data.msg_text);
    if(strncmp(some_data.msg_text,"end",3)==0)
    {
     running=0;
    }
}
if(msgctl(msgid,IPC_RMID,0)==-1)
{
    fprintf(stderr,"msgctl(IPC_RMID) feiled\n");
    exit(EXIT_FAILURE);
}

return 0;
}