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guile/libguile/arbiters.c

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/* Copyright (C) 1995,1996, 1997 Free Software Foundation, Inc.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
* Boston, MA 02111-1307 USA
*
* As a special exception, the Free Software Foundation gives permission
* for additional uses of the text contained in its release of GUILE.
*
* The exception is that, if you link the GUILE library with other files
* to produce an executable, this does not by itself cause the
* resulting executable to be covered by the GNU General Public License.
* Your use of that executable is in no way restricted on account of
* linking the GUILE library code into it.
*
* This exception does not however invalidate any other reasons why
* the executable file might be covered by the GNU General Public License.
*
* This exception applies only to the code released by the
* Free Software Foundation under the name GUILE. If you copy
* code from other Free Software Foundation releases into a copy of
* GUILE, as the General Public License permits, the exception does
* not apply to the code that you add in this way. To avoid misleading
* anyone as to the status of such modified files, you must delete
* this exception notice from them.
*
* If you write modifications of your own for GUILE, it is your choice
* whether to permit this exception to apply to your modifications.
* If you do not wish that, delete this exception notice. */
#include <stdio.h>
#include "_scm.h"
#include "smob.h"
#include "genio.h"
#include "arbiters.h"
/* {Arbiters}
*
* These procedures implement synchronization primitives. Processors
* with an atomic test-and-set instruction can use it here (and not
* SCM_DEFER_INTS).
*/
static long scm_tc16_arbiter;
static int
prinarb (exp, port, pstate)
SCM exp;
SCM port;
scm_print_state *pstate;
{
scm_puts ("#<arbiter ", port);
if (SCM_CAR (exp) & (1L << 16))
scm_puts ("locked ", port);
scm_iprin1 (SCM_CDR (exp), port, pstate);
scm_putc ('>', port);
return !0;
}
SCM_PROC(s_make_arbiter, "make-arbiter", 1, 0, 0, scm_make_arbiter);
SCM
scm_make_arbiter (name)
SCM name;
{
SCM z;
SCM_NEWSMOB (z, scm_tc16_arbiter, name);
return z;
}
SCM_PROC(s_try_arbiter, "try-arbiter", 1, 0, 0, scm_try_arbiter);
SCM
scm_try_arbiter (arb)
SCM arb;
{
SCM_ASSERT ((SCM_TYP16 (arb) == scm_tc16_arbiter), arb, SCM_ARG1, s_try_arbiter);
SCM_DEFER_INTS;
if (SCM_CAR (arb) & (1L << 16))
arb = SCM_BOOL_F;
else
{
SCM_SETCAR (arb, scm_tc16_arbiter | (1L << 16));
arb = SCM_BOOL_T;
}
SCM_ALLOW_INTS;
return arb;
}
SCM_PROC(s_release_arbiter, "release-arbiter", 1, 0, 0, scm_release_arbiter);
SCM
scm_release_arbiter (arb)
SCM arb;
{
SCM_ASSERT ((SCM_TYP16 (arb) == scm_tc16_arbiter), arb, SCM_ARG1, s_release_arbiter);
if (!(SCM_CAR (arb) & (1L << 16)))
return SCM_BOOL_F;
SCM_SETCAR (arb, scm_tc16_arbiter);
return SCM_BOOL_T;
}
void
scm_init_arbiters ()
{
scm_tc16_arbiter = scm_make_smob_type ("arbiter", 0);
scm_set_smob_mark (scm_tc16_arbiter, scm_markcdr);
scm_set_smob_print (scm_tc16_arbiter, prinarb);
#include "arbiters.x"
}