Re: [Chicken-hackers] [PATCH] Change setjmp/longjmp to _setjmp/_longjmp to avoid overhead and fix signal masking bug

[Peter Bex]

On Fri, Jun 15, 2012 at 12:45:28PM +0200, Felix wrote:
> > Other than figuring that out, it would be a good idea to test on mingw
> > and OS X (I was going to do this).  However testing on other platforms
> > like cygwin or Solaris (or more obscure?) is problematic.  It is not
> > really a question of whether _setjmp works but if every platform supports
> > _setjmp.  I don't know if this is something to throw in before the
> > release, if one is coming soon, unless we are going to test every
> > supported platform before release.  Anyone else?
> 
> Changing this IMHO should be postponed until we have a new release.

After some more consideration, I think the signal mask reset bug warrants
fixing it before the next release.  Attached is a better patch which
tries to avoid using fringe POSIX functions and instead simply using
sigsetjmp()/siglongjmp() on platforms where we know they are supported.

After asking on #chicken, "creidiki" tried the old patch on Windows and
mentioned it didn't compile due to an undeclared function _longjmp
(oddly, _setjmp *does* seem to exist...) so I haven't added sigsetjmp
to Windows either.  In any case, Windows doesn't have POSIX signals
anyway so it doesn't matter which flavor of "*jmp" we use there.

If someone using, say, Solaris or Haiku figures that sigsetjmp is
supported on their platform after all, it's a simple matter of adding
the define to Makefile.solaris or Makefile.haiku.  At least this way
it gets fixed on platforms that are known to have the signal problem.

Cheers,
Peter
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0001-Use-sigsetjmp-siglongjmp-instead-of-setjmp-longjmp-o.patch
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