mfork: closing kqueue file descriptor is unsuccessful and leads to 'assert failed' on OSX

[Danappelxx]

Minimal program to reproduce:

#include <libmill.h>

int main(int argc, char *argv[]) {
  goprepare(10, 25000, 300);
  pid_t pid = mfork();
}

compiled with:

clang -o main main.c libmill.dylib -I/usr/local/include

output:

Assert failed: rc == 0 (./kqueue.inc:92)

Using libmill version 1.5 downloaded from the website and compiled with

./configure && make && sudo make install

I'm on OSX 10.11 running clang 7.3.0.

My knowledge of c is very limited but it seems like the assumption made about kqueue in the doc comment (here about how closing it will not return an error) is misguided.

As expected, if I get rid of the goprepare(10, 25000, 300) the fork succeeds.

Let me know if there's anything I can do!

[sustrik]

I don't own an OSX box. Can you possibly run the test in a debugger and check the value of 'errno' after the failed call?

[nirs]

Maybe we should include errno in the error message in these asserts?

Assert failed: rc == 0 (rc=2, errno=13 file=./kqueue.inc:92)

[sustrik]

EACCESS. Interesting. I wonder whether that means that "file descriptor haven't survived the fork." Anyway, I'll try to fix it.

As for including errno into the asserts, yes, something like assert_errno() would be nice. I am to lazy to implement it though. So it's up to you :)

[sustrik]

The problem is now fixed. Tested on OSX (via Travis) and FreeBSD.

Please check and close the ticket if everything goes OK.

[Danappelxx]

Seems to work! Thanks for the quick fix :)