Re: [AD] mzscheme bindings in svn

[Peter Wang <novalazy@xxxxxxxxxx>]

On 2007-04-28, Jon Rafkind <workmin@xxxxxxxxxx> wrote:
> Oh wait I forgot. I did change one fundamental thing about Allegro. In 
> src/x/xsystem.c I had to comment out the signal stuff because mzscheme 
> uses signals for write-barriers with the garbage collector:
> 
> static int _xwin_sysdrv_init(void)
> {
>    char tmp[256];
> 
>    _unix_read_os_type();
>    /*
>    old_sig_abrt = signal(SIGABRT, _xwin_signal_handler);
>    old_sig_fpe  = signal(SIGFPE,  _xwin_signal_handler);
>    old_sig_ill  = signal(SIGILL,  _xwin_signal_handler);
>    old_sig_segv = signal(SIGSEGV, _xwin_signal_handler);
>    old_sig_term = signal(SIGTERM, _xwin_signal_handler);
>    old_sig_int  = signal(SIGINT,  _xwin_signal_handler);
> 
> #ifdef SIGQUIT
>    old_sig_quit = signal(SIGQUIT, _xwin_signal_handler);
> #endif
> */
> 
> Maybe we can wrap those with a
> if ( global_use_signals ){
>   ...
> }
> or something?

That would be fine (but call it __al_xwin_dont_install_signal_handlers
or something).  A dirtier solution would be to save the MzScheme signal
handlers before calling allegro_init(), then restore them immediately
afterwards.  This would work with current and older versions of Allegro.

OTOH, which signals are MzScheme using?  Surely not SIGABRT, SIGSEGV,
SIGTERM, SIGQUIT?

Peter