Can't catch Ignored signals about chan-signal HOT 5 CLOSED

Confirmed, this is a show-stopper problem. We need WINCH and it should work. If it cannot catch these signals, it should not compile, but it should also be fixed. Silently broken is unprofessional fail.

@agatan Obviously, if you bothered to read the man pages, a correct call to pthread_sigmask is needed. A catchable signal must be not blocked, not ignored and have a registered handler to deliver it to.

from chan-signal.

I just ran into this as well. I don't understand, is this something that is fixable given the current architecture of the crate? I could try and open a PR.

from chan-signal.

Just run into this too. I think you are both right. You need to set the signals to be "blocked" and also not "ignored.

From man sigwait:

The signals specified by set should be blocked, but not ignored, at the time of the call to sigwait().

Processes which call sigwait() on ignored signals will wait indefinitely. Ignored signals are dropped immediately by the system, before delivery to a waiting process.

From man sigaction:

A process may specify a handler to which a signal is delivered, or specify that a signal is to be ignored.

From man pthread_sigmask:

Actually these man pages are about the most confusingly written I have ever read, but pthread_sigmask lets you set the "block" bit on a signal.

It would be good if this crate's Readme.md would mention that it doesn't... really.. work :-/

from chan-signal.

And upon reading the code it seems like it does block the signals properly, but just doesn't set any signal handlers.

A workaround in your code is something like this:

extern crate libc;
use libc::sighandler_t;
use libc::{c_int, c_void, SIGWINCH};
use libc::signal;

extern fn handler(_: c_int) {}

fn get_handler() -> sighandler_t {
    handler as extern fn(c_int) as *mut c_void as sighandler_t
}

fn main() {
	unsafe { signal(SIGWINCH, get_handler()); }
...

I have verified that this works and I now receive SIGNWINCH, however this should really be fixed in the library by doing the above for any signals the user requests.

from chan-signal.

This crate is now deprecated. See: https://users.rust-lang.org/t/ann-chan-is-deprecated-use-crossbeam-channel-instead/19251

from chan-signal.