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/*-------------------------------------------------------------------------
*
* pqsignal.c--
* reliable BSD-style signal(2) routine stolen from RWW who stole it
* from Stevens...
*
* Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/libpq/pqsignal.c,v 1.5 1996/12/26 22:07:08 momjian Exp $
*
* NOTES
* This shouldn't be in libpq, but the monitor and some other
* things need it...
*
* A NOTE ABOUT SIGNAL HANDLING ACROSS THE VARIOUS PLATFORMS.
*
* config.h defines the macro USE_POSIX_SIGNALS for some platforms and
* not for others. This file and pqsignal.h use that macro to decide
* how to handle signalling.
*
* signal(2) handling - this is here because it affects some of
* the frontend commands as well as the backend server.
*
* Ultrix and SunOS provide BSD signal(2) semantics by default.
*
* SVID2 and POSIX signal(2) semantics differ from BSD signal(2)
* semantics. We can use the POSIX sigaction(2) on systems that
* allow us to request restartable signals (SA_RESTART).
*
* Some systems don't allow restartable signals at all unless we
* link to a special BSD library.
*
* We devoutly hope that there aren't any systems that provide
* neither POSIX signals nor BSD signals. The alternative
* is to do signal-handler reinstallation, which doesn't work well
* at all.
* ------------------------------------------------------------------------*/
#include <postgres.h>
#include <signal.h>
#include <libpq/pqsignal.h>
pqsigfunc
pqsignal(int signo, pqsigfunc func)
{
#if !defined(USE_POSIX_SIGNALS)
return signal(signo, func);
#else
struct sigaction act, oact;
act.sa_handler = func;
sigemptyset(&act.sa_mask);
act.sa_flags = 0;
if (signo != SIGALRM) {
act.sa_flags |= SA_RESTART;
}
if (sigaction(signo, &act, &oact) < 0)
return(SIG_ERR);
return(oact.sa_handler);
#endif /* !USE_POSIX_SIGNALS */
}
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