Subject: Re: bug#14569: 24.3.50; bootstrap fails on Cygwin

From: Ken Brown <[email-masked]>
Date: Tue, 25 Jun 2013 11:51:20 -0400

On 6/25/2013 10:51 AM, Paul Eggert wrote:
> On 06/25/2013 06:55 AM, Ken Brown wrote:
>> I'm puzzled by the asymmetry between block_child_signal and unblock_child_signal.  The first blocks SIGCHLD, while the second unblocks *all* signals.  Why is this the right thing to do?
>>
>> Ken
>
> I didn't write that code, but here's my guess.

According to 'bzr log', you introduced those two functions in rev 111081.

> Emacs normally runs with all signals unblocked.
> Unblocking everything is the right thing to do,
> if there's a bug elsewhere in Emacs that inadvertently
> leaves signals blocked.

I still don't get the asymmetry.  By your reasoning, it would seem that 
block_child_signal should set the mask so that only SIGCHLD is blocked. 
  And can unblock_child_signal really be sure that there's no good 
reason for a signal to be blocked?

But I don't want to belabor this.  You know much more about this than I 
do, so if you're sure the existing code is right, I'll drop it.

Ken