msgsend.c

msgsend函数的使用例子

#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/msg.h>
#include <stdio.h>
#include <string.h>
#define MSGSZ     128
/*
 * Declare the message structure.
 */

typedef struct msgbuf {
         long    mtype;
         char    mtext[MSGSZ];
} message_buf;

main(){
    int msqid;
    int msgflg = IPC_CREAT | 0666;
    key_t key;

    message_buf sbuf;
    size_t buf_length;
	
    /*
     * Get the message queue id for the     
	 * "name" 1234, which was created by
     * the server.     
	 */    
	 
	 key = 1234;
	
	(void) fprintf(stderr, 
			"\nmsgget: Calling msgget(%#lx,\%#o)\n",
			key, msgflg);
    
	if ((msqid = msgget(key, msgflg )) < 0) {
	    perror("msgget");
        exit(1);    
	}    
	else 
		(void) fprintf(stderr,
			"msgget: msgget succeeded: msqid = %d\n", 
			msqid);
    /*     
	 * We'll send message type 1     
	 */         
	 
	 sbuf.mtype = 1;    
     (void) fprintf(stderr,
			"msgget: msgget succeeded: msqid = %d\n", 
			msqid);    
     (void) strcpy(sbuf.mtext, "Did you get this?");    
     (void) fprintf(stderr,
			"msgget: msgget succeeded: msqid = %d\n", 
			msqid);    
     buf_length = strlen(sbuf.mtext) ;            
	 
	 /*     
	  * Send a message.     
	  */
     if (msgsnd(msqid, &sbuf, buf_length, IPC_NOWAIT) < 0) {
		printf ("%d, %d, %s, %d\n", msqid, sbuf.mtype, sbuf.mtext, buf_length);
        perror("msgsnd");        
		exit(1);    
	 }   
	 else 
		printf("Message: \"%s\" Sent\n", sbuf.mtext);          
	
	 exit(0);
}