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7ee92fcefd
* scmsigs.c (scm_sigaction): add SA_RESTART to flags only if HAVE_RESTARTABLE_SYSCALLS. (scm_init_scmsigs): use siginterrupt if it's available. not everyone who has restartable syscalls has SA_RESTART it seems. (scm_sigaction): use scm_num2long/scm_long2num when converting SIG_DFL/SIG_IGN, in case it doesn't fit in an INUM. use scm_integer_p to test the type.
482 lines
12 KiB
C
482 lines
12 KiB
C
/* Copyright (C) 1995, 1996, 1997, 1998, 1999 Free Software Foundation, Inc.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this software; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
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* Boston, MA 02111-1307 USA
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*
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* As a special exception, the Free Software Foundation gives permission
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* for additional uses of the text contained in its release of GUILE.
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*
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* The exception is that, if you link the GUILE library with other files
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* to produce an executable, this does not by itself cause the
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* resulting executable to be covered by the GNU General Public License.
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* Your use of that executable is in no way restricted on account of
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* linking the GUILE library code into it.
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*
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* This exception does not however invalidate any other reasons why
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* the executable file might be covered by the GNU General Public License.
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*
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* This exception applies only to the code released by the
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* Free Software Foundation under the name GUILE. If you copy
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* code from other Free Software Foundation releases into a copy of
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* GUILE, as the General Public License permits, the exception does
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* not apply to the code that you add in this way. To avoid misleading
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* anyone as to the status of such modified files, you must delete
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* this exception notice from them.
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*
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* If you write modifications of your own for GUILE, it is your choice
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* whether to permit this exception to apply to your modifications.
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* If you do not wish that, delete this exception notice. */
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#include <stdio.h>
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#include <signal.h>
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#include "_scm.h"
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#include "async.h"
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#include "eval.h"
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#include "scmsigs.h"
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#ifdef HAVE_UNISTD_H
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#include <unistd.h>
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#endif
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/* The thread system has its own sleep and usleep functions. */
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#ifndef USE_THREADS
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#if defined(MISSING_SLEEP_DECL)
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int sleep ();
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#endif
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#if defined(HAVE_USLEEP) && defined(MISSING_USLEEP_DECL)
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int usleep ();
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#endif
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#endif
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#ifdef USE_MIT_PTHREADS
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#undef signal
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#define signal pthread_signal
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#endif
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/* SIGRETTYPE is the type that signal handlers return. See <signal.h> */
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#ifdef RETSIGTYPE
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# define SIGRETTYPE RETSIGTYPE
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#else
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# ifdef STDC_HEADERS
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# define SIGRETTYPE void
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# else
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# define SIGRETTYPE int
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# endif
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#endif
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/* take_signal is installed as the C signal handler whenever a Scheme
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handler is set. when a signal arrives, take_signal marks the corresponding
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element of got_signal and marks signal_async. the thunk in signal_async
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(sys_deliver_signals) will be run at the next opportunity, outside a
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critical section. sys_deliver_signals runs each Scheme handler for
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which got_signal is set. */
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static SCM signal_async;
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static char got_signal[NSIG];
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/* a Scheme vector of handler procedures. */
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static SCM *signal_handlers;
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/* saves the original C handlers, when a new handler is installed.
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set to SIG_ERR if the original handler is installed. */
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#ifdef HAVE_SIGACTION
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static struct sigaction orig_handlers[NSIG];
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#else
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static SIGRETTYPE (*orig_handlers)(int)[NSIG];
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#endif
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static SIGRETTYPE
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take_signal (int signum)
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{
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int saved_errno = errno;
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SCM ignored;
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if (!scm_ints_disabled)
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{
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/* For reasons of speed, the SCM_NEWCELL macro doesn't defer
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interrupts. Instead, it first sets its argument to point to
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the first cell in the list, and then advances the freelist
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pointer to the next cell. Now, if this procedure is
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interrupted, the only anomalous state possible is to have
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both SCM_NEWCELL's argument and scm_freelist pointing to the
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same cell. To deal with this case, we always throw away the
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first cell in scm_freelist here.
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At least, that's the theory. I'm not convinced that that's
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the only anomalous path we need to worry about. */
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SCM_NEWCELL (ignored);
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}
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got_signal[signum] = 1;
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#if HAVE_SIGACTION
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/* unblock the signal before the scheme handler gets to run, since
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it may use longjmp to escape (i.e., throw an exception). */
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{
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sigset_t set;
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sigemptyset (&set);
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sigaddset (&set, signum);
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sigprocmask (SIG_UNBLOCK, &set, NULL);
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}
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#endif
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scm_system_async_mark (signal_async);
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errno = saved_errno;
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}
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static SCM
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sys_deliver_signals (void)
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{
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int i;
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for (i = 0; i < NSIG; i++)
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{
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if (got_signal[i])
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{
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/* The flag is reset before calling the handler in case the
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handler doesn't return. If the handler doesn't return
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but leaves other signals flagged, they their handlers
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will be applied some time later when the async is checked
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again. It would probably be better to reset the flags
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after doing a longjmp. */
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got_signal[i] = 0;
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#ifndef HAVE_SIGACTION
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signal (i, take_signal);
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#endif
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scm_apply (SCM_VELTS (*signal_handlers)[i],
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scm_listify (SCM_MAKINUM (i), SCM_UNDEFINED),
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SCM_EOL);
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}
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}
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return SCM_UNSPECIFIED;
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}
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/* user interface for installation of signal handlers. */
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SCM_PROC(s_sigaction, "sigaction", 1, 2, 0, scm_sigaction);
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SCM
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scm_sigaction (SCM signum, SCM handler, SCM flags)
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{
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int csig;
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#ifdef HAVE_SIGACTION
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struct sigaction action;
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struct sigaction old_action;
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#else
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SIGRETTYPE (* chandler) (int);
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SIGRETTYPE (* old_chandler) (int);
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#endif
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int query_only = 0;
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int save_handler = 0;
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SCM *scheme_handlers = SCM_VELTS (*signal_handlers);
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SCM old_handler;
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SCM_ASSERT (SCM_INUMP (signum), signum, SCM_ARG1, s_sigaction);
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csig = SCM_INUM (signum);
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#if defined(HAVE_SIGACTION)
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#if defined(SA_RESTART) && defined(HAVE_RESTARTABLE_SYSCALLS)
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/* don't allow SA_RESTART to be omitted if HAVE_RESTARTABLE_SYSCALLS
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is defined, since libguile would be likely to produce spurious
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EINTR errors. */
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action.sa_flags = SA_RESTART;
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#else
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action.sa_flags = 0;
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#endif
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if (!SCM_UNBNDP (flags))
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{
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SCM_ASSERT (SCM_INUMP (flags), flags, SCM_ARG3, s_sigaction);
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action.sa_flags |= SCM_INUM (flags);
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}
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sigemptyset (&action.sa_mask);
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#endif
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SCM_DEFER_INTS;
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old_handler = scheme_handlers[csig];
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if (SCM_UNBNDP (handler))
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query_only = 1;
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else if (scm_integer_p (handler) == SCM_BOOL_T)
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{
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if (scm_num2long (handler, (char *) SCM_ARG2, s_sigaction)
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== (long) SIG_DFL
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|| scm_num2long (handler, (char *) SCM_ARG2, s_sigaction)
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== (long) SIG_IGN)
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{
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#ifdef HAVE_SIGACTION
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action.sa_handler = (SIGRETTYPE (*) (int)) SCM_INUM (handler);
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#else
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chandler = (SIGRETTYPE (*) (int)) SCM_INUM (handler);
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#endif
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scheme_handlers[csig] = SCM_BOOL_F;
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}
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else
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scm_out_of_range (s_sigaction, handler);
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}
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else if (SCM_FALSEP (handler))
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{
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/* restore the default handler. */
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#ifdef HAVE_SIGACTION
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if (orig_handlers[csig].sa_handler == SIG_ERR)
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query_only = 1;
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else
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{
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action = orig_handlers[csig];
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orig_handlers[csig].sa_handler = SIG_ERR;
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scheme_handlers[csig] = SCM_BOOL_F;
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}
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#else
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if (orig_handlers[csig] == SIG_ERR)
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query_only = 1;
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else
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{
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chandler = orig_handlers[csig];
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orig_handlers[csig] = SIG_ERR;
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scheme_handlers[csig] = SCM_BOOL_F;
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}
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#endif
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}
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else
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{
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SCM_ASSERT (SCM_NIMP (handler), handler, SCM_ARG2, s_sigaction);
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#ifdef HAVE_SIGACTION
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action.sa_handler = take_signal;
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if (orig_handlers[csig].sa_handler == SIG_ERR)
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save_handler = 1;
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#else
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chandler = take_signal;
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if (orig_handlers[csig] == SIG_ERR)
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save_handler = 1;
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#endif
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scheme_handlers[csig] = handler;
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}
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#ifdef HAVE_SIGACTION
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if (query_only)
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{
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if (sigaction (csig, 0, &old_action) == -1)
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scm_syserror (s_sigaction);
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}
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else
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{
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if (sigaction (csig, &action , &old_action) == -1)
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scm_syserror (s_sigaction);
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if (save_handler)
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orig_handlers[csig] = old_action;
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}
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if (old_action.sa_handler == SIG_DFL || old_action.sa_handler == SIG_IGN)
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old_handler = scm_long2num ((long) old_action.sa_handler);
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SCM_ALLOW_INTS;
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return scm_cons (old_handler, SCM_MAKINUM (old_action.sa_flags));
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#else
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if (query_only)
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{
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if ((old_chandler = signal (csig, SIG_IGN)) == SIG_ERR)
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scm_syserror (s_sigaction);
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if (signal (csig, old_chandler) == SIG_ERR)
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scm_syserror (s_sigaction);
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}
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else
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{
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if ((old_chandler = signal (csig, chandler)) == SIG_ERR)
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scm_syserror (s_sigaction);
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if (save_handler)
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orig_handlers[csig] = old_chandler;
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}
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if (old_chandler == SIG_DFL || old_chandler == SIG_IGN)
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old_handler = scm_long2num (old_chandler);
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SCM_ALLOW_INTS;
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return scm_cons (old_handler, SCM_MAKINUM (0));
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#endif
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}
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SCM_PROC (s_restore_signals, "restore-signals", 0, 0, 0, scm_restore_signals);
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SCM
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scm_restore_signals (void)
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{
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int i;
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SCM *scheme_handlers = SCM_VELTS (*signal_handlers);
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for (i = 0; i < NSIG; i++)
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{
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#ifdef HAVE_SIGACTION
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if (orig_handlers[i].sa_handler != SIG_ERR)
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{
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if (sigaction (i, &orig_handlers[i], NULL) == -1)
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scm_syserror (s_restore_signals);
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orig_handlers[i].sa_handler = SIG_ERR;
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scheme_handlers[i] = SCM_BOOL_F;
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}
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#else
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if (orig_handlers[i] != SIG_ERR)
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{
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if (signal (i, orig_handlers[i]) == SIG_ERR)
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scm_syserror (s_restore_signals);
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orig_handlers[i] = SIG_ERR;
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scheme_handlers[i] = SCM_BOOL_F;
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}
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#endif
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}
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return SCM_UNSPECIFIED;
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}
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SCM_PROC(s_alarm, "alarm", 1, 0, 0, scm_alarm);
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SCM
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scm_alarm (i)
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SCM i;
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{
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unsigned int j;
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SCM_ASSERT (SCM_INUMP (i) && (SCM_INUM (i) >= 0), i, SCM_ARG1, s_alarm);
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j = alarm (SCM_INUM (i));
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return SCM_MAKINUM (j);
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}
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#ifdef HAVE_PAUSE
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SCM_PROC(s_pause, "pause", 0, 0, 0, scm_pause);
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SCM
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scm_pause ()
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{
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pause ();
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return SCM_UNSPECIFIED;
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}
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#endif
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SCM_PROC(s_sleep, "sleep", 1, 0, 0, scm_sleep);
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SCM
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scm_sleep (i)
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SCM i;
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{
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unsigned long j;
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SCM_ASSERT (SCM_INUMP (i) && (SCM_INUM (i) >= 0), i, SCM_ARG1, s_sleep);
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#ifdef USE_THREADS
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j = scm_thread_sleep (SCM_INUM(i));
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#else
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j = sleep (SCM_INUM(i));
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#endif
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return scm_ulong2num (j);
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}
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#if defined(USE_THREADS) || defined(HAVE_USLEEP)
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SCM_PROC(s_usleep, "usleep", 1, 0, 0, scm_usleep);
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SCM
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scm_usleep (i)
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SCM i;
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{
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SCM_ASSERT (SCM_INUMP (i) && (SCM_INUM (i) >= 0), i, SCM_ARG1, s_usleep);
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#ifdef USE_THREADS
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/* If we have threads, we use the thread system's sleep function. */
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{
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unsigned long j = scm_thread_usleep (SCM_INUM (i));
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return scm_ulong2num (j);
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}
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#else
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#ifdef USLEEP_RETURNS_VOID
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usleep (SCM_INUM (i));
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return SCM_INUM0;
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#else
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{
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int j = usleep (SCM_INUM (i));
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return SCM_MAKINUM (j);
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}
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#endif
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#endif
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}
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#endif /* GUILE_ISELECT || HAVE_USLEEP */
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SCM_PROC(s_raise, "raise", 1, 0, 0, scm_raise);
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SCM
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scm_raise(sig)
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SCM sig;
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{
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SCM_ASSERT(SCM_INUMP(sig), sig, SCM_ARG1, s_raise);
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SCM_DEFER_INTS;
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if (kill (getpid (), (int) SCM_INUM (sig)) != 0)
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scm_syserror (s_raise);
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SCM_ALLOW_INTS;
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return SCM_UNSPECIFIED;
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}
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void
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scm_init_scmsigs ()
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{
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SCM thunk;
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int i;
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signal_handlers =
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SCM_CDRLOC (scm_sysintern ("signal-handlers",
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scm_make_vector (SCM_MAKINUM (NSIG),
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SCM_BOOL_F)));
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thunk = scm_make_gsubr ("%deliver-signals", 0, 0, 0,
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sys_deliver_signals);
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signal_async = scm_system_async (thunk);
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for (i = 0; i < NSIG; i++)
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{
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got_signal[i] = 0;
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#ifdef HAVE_SIGACTION
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orig_handlers[i].sa_handler = SIG_ERR;
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#else
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orig_handlers[i] = SIG_ERR;
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#endif
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#ifdef HAVE_RESTARTABLE_SYSCALLS
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/* If HAVE_RESTARTABLE_SYSCALLS is defined, it's important that
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signals really are restartable. don't rely on the same
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run-time that configure got: reset the default for every signal.
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*/
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#ifdef HAVE_SIGINTERRUPT
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siginterrupt (i, 0);
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#elif defined SA_RESTART
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{
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struct sigaction action;
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sigaction (i, NULL, &action);
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if (!(action.sa_flags & SA_RESTART))
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{
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action.sa_flags &= SA_RESTART;
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sigaction (i, &action, NULL);
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}
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}
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#endif
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/* if neither siginterrupt nor SA_RESTART are available we may
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as well assume that signals are always restartable. */
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#endif
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}
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scm_sysintern ("NSIG", scm_long2num (NSIG));
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scm_sysintern ("SIG_IGN", scm_long2num ((long) SIG_IGN));
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scm_sysintern ("SIG_DFL", scm_long2num ((long) SIG_DFL));
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#ifdef SA_NOCLDSTOP
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scm_sysintern ("SA_NOCLDSTOP", scm_long2num (SA_NOCLDSTOP));
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#endif
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#ifdef SA_RESTART
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scm_sysintern ("SA_RESTART", scm_long2num (SA_RESTART));
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#endif
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#include "scmsigs.x"
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}
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