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(scm_gensym): Use scm_i_misc_mutex around gensym_counter

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update, for thread safety.
(gensym_counter): Move into scm_gensym which is its only user.
(scm_init_symbols): No need to explicitly initialize gensym_counter.
This commit is contained in:
Kevin Ryde 2004-07-31 01:08:20 +00:00
commit 7426a638b7
1 changed files with 11 additions and 5 deletions
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16
libguile/symbols.c
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@ -1,4 +1,4 @@
/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2003 Free Software Foundation, Inc.
/* Copyright (C) 1995,1996,1997,1998,2000,2001, 2003, 2004 Free Software Foundation, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
@ -264,8 +264,6 @@ SCM_DEFINE (scm_string_to_symbol, "string->symbol", 1, 0, 0,
#define MAX_PREFIX_LENGTH 30
static int gensym_counter;
SCM_DEFINE (scm_gensym, "gensym", 0, 1, 0,
(SCM prefix),
"Create a new symbol with a name constructed from a prefix and\n"
@ -275,6 +273,8 @@ SCM_DEFINE (scm_gensym, "gensym", 0, 1, 0,
"resetting the counter.")
#define FUNC_NAME s_scm_gensym
{
static int gensym_counter = 0;
char buf[MAX_PREFIX_LENGTH + SCM_INTBUFLEN];
char *name = buf;
size_t len;
@ -293,7 +293,14 @@ SCM_DEFINE (scm_gensym, "gensym", 0, 1, 0,
memcpy (name, SCM_STRING_CHARS (prefix), len);
}
{
int n_digits = scm_iint2str (gensym_counter++, 10, &name[len]);
int n, n_digits;
/* mutex in case another thread looks and incs at the exact same moment */
scm_mutex_lock (&scm_i_misc_mutex);
n = gensym_counter++;
scm_mutex_unlock (&scm_i_misc_mutex);
n_digits = scm_iint2str (n, 10, &name[len]);
SCM res = scm_mem2symbol (name, len + n_digits);
if (name != buf)
free (name);
@ -414,7 +421,6 @@ scm_symbols_prehistory ()
void
scm_init_symbols ()
{
gensym_counter = 0;
#include "libguile/symbols.x"
}