Re: $SIG{'INT'} = 'BLOCK'

["Mark Mielke" <markm@nortelnetworks.com>]

Personally, I like this extension.

mark

On Tue, Jan 11, 2000 at 07:09:42AM -0700, "Tom Christiansen" wrote:
> One request: if one is planning on tinkering with the signal system,
> might one please consider whether to implement a special 'BLOCK' status,
> by extension to 'IGNORE' and 'DEFAULT'?  
> 
> Compare the ease of this simple assignment:
> 
>     $SIG{INT} = 'BLOCK';
> 
> or in its own block:
> 
>     {
> 	local $SIG{INT} = 'BLOCK';
> 	##############################
> 	# protected stuff happens here
> 	##############################
>     } 
>     # pending deliveries trigger right here; careful to finish
>     # all of block's destructors first, though
> 
> with the complexity of implementing the same under the status quo:
> 
>     use POSIX qw(:signal_h);
> 
>     $sigset = POSIX::SigSet->new(SIGINT);       
>     $old_sigset = POSIX::SigSet->new;          
>     unless (defined sigprocmask(SIG_BLOCK, $sigset, $old_sigset)) {
>         die "Could not block SIGINT\n";
>     }
> 
>     ##############################
>     # protected stuff happens here
>     ##############################
> 
>     unless (sigprocmask(SIG_UNBLOCK, $old_sigset)) {
>         die "Could not unblock SIGINT\n";
>     }
> 
> 
> Surely all shall agree that assign 'BLOCK' to a %SIG entry is rather
> easier than all that.  But is this something that should be easy or not?
> It's easy to infer that it might well exist, given the current interface?
> Can anyone think of solid reasons--beyond lack of roundtuits, of
> course--why one should not do this?  (And I consider the fact that POSIX
> signal semantics and SIG_BLOCK are not ubiquitously implemented to be
> an insufficient disincentive: signals themselves are not universally
> respected, but we can access them from Perl if they are present.)
> 
> --tom

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References to:

Larry Wall <larry@wall.org>
Tom Christiansen <tchrist@jhereg.perl.com>

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