Hi! I already asked this question on stackoverflow, but it didn't get any attention, so here it goes.
Is there a way to make FreeBSD copy POSIX message queue descriptions when forking? I know it doesn't by default, because I wrote a test program:
I compiled it under both Linux and FreeBSD 9.2 using
though.
Is there a way to make FreeBSD copy POSIX message queue descriptions when forking? I know it doesn't by default, because I wrote a test program:
Code:
#include <stdio.h> #include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <mqueue.h>
#include <errno.h>
#include <fcntl.h>
int main() {
struct mq_attr attrs;
attrs.mq_maxmsg = 10;
attrs.mq_msgsize = sizeof(int);
const char name[] = "/test-queue";
mqd_t q = mq_open(name, O_CREAT | O_RDWR, 0600, &attrs);
if (q == (mqd_t)-1) {
perror("mq_open");
exit(EXIT_FAILURE);
}
mq_unlink(name); // it doesn't matter if I do this at the end or not
if (fork()) {
int msg = 666;
if (mq_send(q, (const char *)&msg, sizeof(msg), 1)) {
perror("mq_send");
exit(EXIT_FAILURE);
}
} else {
int msg;
unsigned priority;
if (mq_receive(q, (char *)&msg, sizeof(msg), &priority) == -1) {
perror("mq_receive");
exit(EXIT_FAILURE);
}
printf("%d\n", msg);
}
mq_close(q);
return 0;
} gcc -std=c99 -Wall -o mqtest mqtest.c -lrt, and under Linux it works. Under FreeBSD I get
Code:
mq_receive: Bad file descriptor