[fpc-pascal] Stopping daemon in linux

["Vinzent Höfler"]

Jonas Maebe <jonas.maebe at elis.ugent.be>:

> On 09 Nov 2009, at 21:03, Michael Van Canneyt wrote:
> 
> > On Mon, 9 Nov 2009, "Vinzent Höfler" wrote:
> >
> >> As wrong as in "Don't call most system functions from within a  
> >> signal handler.", maybe?
> >
> > Hmm... In that case, many exceptions would not work either ?
> 
> The sigaction handlers for catching exceptions have been fixed quite a  
> while ago already to only collect the necessary information from the  
> signal context, [...]

Additionally, signals causing run-time exceptions are triggered by the code itself, meaning things like SIGSEGV[*] are not actually "interrupting", rather they synchronously "transfer control" in a relatively well-defined way.

Maybe the analogy to good ol' DOS programming helps: Then signals are just interrupts, "synchronous" signals are "int xx" instructions, while "asynchronous" are real "hardware interrupts". Unfortunately you'll never know which will be which. ;)


Vinzent.

[*] Of course, the SIGSEGV still could have been sent from another process making it interrupting and asynchronous like any other signal.
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