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遇到 mq_open: Permission denied

请看：

Mounting the message queue file system

       On Linux, message queues are created in a virtual file system.   (Other        implementations  may  also  provide such a feature, but the details are        likely to differ.)  This file system can be mounted (by the  superuser)        using the following commands:            # mkdir /dev/mqueue            # mount -t mqueue none /dev/mqueue

执行上面两条命令OK，

还是遇到同样的问题：

再看

Each message queue  is  identi fied by a name of the form /somename.  Two processes can operate on the

same queue by passing the same name to mq_open().

也就是说，消息的队列的命名方式为/mq_name

其它命名方式都不对，像/tmp/mq.2342是不对的。

OK，以下为测试代码：

/* ============================================================================ Name        : mq_creat.c ============================================================================ */#include 
   
    #include 
    
     #include 
     
      #include 
      
       #define FILE_MODE (S_IRUSR|S_IWUSR|S_IRGRP|S_IROTH)int main(int argc, char** argv) {	mqd_t mqd;	int c, flags;	flags = O_RDWR | O_CREAT;	while ((c = getopt(argc, argv, "e")) != -1) {		switch (c) {		case 'e':			flags |= O_EXCL;			break;		}	}	if (optind != argc - 1) {		printf("Invalid arg\n");		return 1;	}	mqd = mq_open(argv[optind], flags, FILE_MODE, NULL);	if (mqd == -1) {		perror("mq_open");		return 2;	}	mq_close(mqd);	return 0;}
      
     
    
   

不懂一定要看man pages， 

如：man 7 mq_overview

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