newlib's waitselect() and Ctrl-C

I was expecting newlib's waitselect() to work like the WaitSelect() in bsdsocket.library, but the Ctrl-C handling seems to be broken.

If I send a Ctrl-C to a task waiting in waitselect() using netshutdown, the task just goes **BREAK and everything freezes because Intuition or something gets upset.

WaitSelect(), in contrast, returns -1 on a Ctrl-C so it can be caught by the application.

Usually I'll Wait() on a SIGBREAKF_CTRLC, but adding that to the signal mask in waitselect() just causes a spurious Ctrl-C to be received.

Any suggestions how to work around this? Or does it need fixing in newlib?

It's likely not breaking at the waitselect() but at any io functions that does a chkabort() (or equiv ) so you need to install a signal handler for SIG_BREAK.

@Chris

If you want to do your own CTRL-C handling you have to either disable the clib's CTRL-C signal handling or avoid all clib function calls.

You can disable newlib break signal handling by:
signal(SIGINT, SIG_IGN);
signal(SIGTERM, SIG_IGN);

The above code is from SRec. Only one of them corresponds to CTRL-C (maybe SIGINT?) but disabling both of them just to be safe doesn't hurt either.

@salass00

It's SIGINT apparently.

I thought I was already doing this, but I'm not, so that's likely the problem.

@salass00

That stopped it terminating in waitselect, but waitselect is still not returning -1 when it receives a Ctrl-C, and adding a SIGBREAKF_CTRLC to the signal mask is still sporadically causing that bit to be returned set.

So it's an improvement but still not quite right.

WaitSelect() doesn't return -1 on CTR-C but on the standard break sigbnal set by SBTC_BREAKMASK (which by default is CTRL-C) perhaps since CTRL_C is handled by the c library bsdsocket library is open with this disabled? (it's also an error case of course you need to test for EINTR but you probably know that).

The spurious returning with SIG_BREAKF_CTRLC set sounds odd though. There no other process that could be sending this to your process?

@broadblues

Quote:

No; if I use Wait() it doesn't happen.