signals on windows

[Andrew Dunstan <andrew(at)dunslane(dot)net>]

here's what I was going to put into initdb.c for signal handling - 
comments welcome - as I think about it more I'm strongly leaning to the 
"set a flag" solution - we'd check for the flag before outputting "ok" 
in various places.

cheers

andrew

/*
* signal handler in case we are interrupted.
*
* The Windows runtime docs at
* http://msdn.microsoft.com/library/en-us/vclib/html/_crt_signal.asp
* specifically forbid a number of things being done from a signal handler,
* most of which we do :-) (specifically, we do IO, mem allocation and 
system
* calls). Also note the behaviour of Windows with SIGINT, which says this:
*   Note   SIGINT is not supported for any Win32 application, including
*   Windows 98/Me and Windows NT/2000/XP. When a CTRL+C interrupt occurs,
*   Win32 operating systems generate a new thread to specifically handle
*   that interrupt. This can cause a single-thread application such as 
UNIX,
*   to become multithreaded, resulting in unexpected behavior.
* I have no idea how to handle this. (Strange they call UNIX an 
application!)
* So this will need some testing on Windows.
* One alternative might be to set a flag that we periodically check for.
*
*/

static void
trapsig(int signum)
{
 fputs("Caught Signal.\n",stderr);
 exit_nicely();
}

[snip]

#ifdef SIGHUP  
   pqsignal(SIGHUP,trapsig);
#endif
#ifdef SIGINT
   pgsignal(SIGINT,trapsig);
#endif
#ifdef SIGQUIT
   pgsignal(SIGQUIT,trapsig);
#endif
#ifdef SIGTERM
   pgsignal(SIGTERM,trapsig);
#endif