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Diffstat (limited to 'libguile/arbiters.c')
-rw-r--r-- | libguile/arbiters.c | 150 |
1 files changed, 150 insertions, 0 deletions
diff --git a/libguile/arbiters.c b/libguile/arbiters.c new file mode 100644 index 000000000..d5e374b42 --- /dev/null +++ b/libguile/arbiters.c @@ -0,0 +1,150 @@ +/* Copyright (C) 1995,1996 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, 675 Mass Ave, Cambridge, MA 02139, 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" + + +/* {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; + +#ifdef __STDC__ +static int +prinarb (SCM exp, SCM port, int writing) +#else +static int +prinarb (exp, port, writing) + SCM exp; + SCM port; + int writing; +#endif +{ + scm_gen_puts (scm_regular_string, "#<arbiter ", port); + if (SCM_CAR (exp) & (1L << 16)) + scm_gen_puts (scm_regular_string, "locked ", port); + scm_iprin1 (SCM_CDR (exp), port, writing); + scm_gen_putc ('>', port); + return !0; +} + +static scm_smobfuns arbsmob = +{ + scm_markcdr, scm_free0, prinarb, 0 +}; + +SCM_PROC(s_make_arbiter, "make-arbiter", 1, 0, 0, scm_make_arbiter); +#ifdef __STDC__ +SCM +scm_make_arbiter (SCM name) +#else +SCM +scm_make_arbiter (name) + SCM name; +#endif +{ + register SCM z; + SCM_NEWCELL (z); + SCM_CDR (z) = name; + SCM_CAR (z) = scm_tc16_arbiter; + return z; +} + +SCM_PROC(s_try_arbiter, "try-arbiter", 1, 0, 0, scm_try_arbiter); +#ifdef __STDC__ +SCM +scm_try_arbiter (SCM arb) +#else +SCM +scm_try_arbiter (arb) + SCM arb; +#endif +{ + 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_CAR (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); +#ifdef __STDC__ +SCM +scm_release_arbiter (SCM arb) +#else +SCM +scm_release_arbiter (arb) + SCM arb; +#endif +{ + 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_CAR (arb) = scm_tc16_arbiter; + return SCM_BOOL_T; +} + + +#ifdef __STDC__ +void +scm_init_arbiters (void) +#else +void +scm_init_arbiters () +#endif +{ + scm_tc16_arbiter = scm_newsmob (&arbsmob); +#include "arbiters.x" +} + |