I'm trying to use message queues on Sun OS 5.6 with Workshop 5 C++. The following command should create one for me:
mqd_t q = mq_open("my_q", O_CREATE | O_RDWR)
This returns -1 and errno is 16 (Invalid argument). If I use "/my_q", it still returns -1 but the error code is 0. Is there a special queue name that I should be using? Any help would be appreciated,
Bruce Edgerton
I did same thing as above description on Solaris 2.6 and WorkShop 4.0 C++. It returns -1 and errno is 16 (Invalid argument). I did use "/my_q" as name for message queue. Here is my code:
open_flags = O_CREAT|O_RDWR;
mqfd = mq_open("/myipc",O_CREAT|O_RDWR,644,0);
if (mqfd == (mqd_t)-1)
{
perror("mq_open failure from main");
exit(0);
};
Anything wrong? Please help
Howard
Howard,
Your piece of code should work as it is, but the error you
report is confusing. Errno 16 is actually EBUSY which is
"Mount device busy". The "Invalid argument" error has an errno
code of 22.
Here is a sample piece of code that worked fine:
<pre>
#include <stdio.h>
#include <mqueue.h>
#include <errno.h>
main(int argc, char **argv)
{
mqd_tmqfd;
mqfd = mq_open("/my_mq", O_CREAT|O_RDWR, 644, 0);
if (mqfd == (mqd_t)-1)
{
perror("mq_open failure from main");
printf("Errno = %d\n",errno);
exit(0);
}
else
{
printf("Message Queue opened successfully (%d)\n", (int)mqfd);
}
}
</PRE>
If you still have problems, then try running your program with
truss to see what's going wrong. You can also check the files
which mq_open creates on the file system. On Solaris 2.6,
three files are created in /tmp for every message queues:
<pre>
ls -la /tmp
-rw-rw-1 guestss-ts132632 Aug 14 11:10 /tmp/.MQDmy_mq
-rw-rw-rw-1 guestss-ts 0 Aug 14 11:10 /tmp/.MQLmy_mq
--w-r--1 guestss-ts 0 Aug 14 11:10 /tmp/.MQPmy_mq
</pre>
Regards,
Caryl
Sun Developer Technical Support
