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author | Bruno Haible <bruno@clisp.org> | 2002-12-11 20:31:00 +0000 |
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committer | Bruno Haible <bruno@clisp.org> | 2002-12-11 20:31:00 +0000 |
commit | 336175d085dac321bc026534f4d9193c092183d3 (patch) | |
tree | e8ee259a649fbb354b674c88063dee0ff7cca565 /lib/unsetenv.c | |
parent | a0483c10aadde639ae071597c221b604f7f5acf5 (diff) | |
download | gnulib-336175d085dac321bc026534f4d9193c092183d3.tar.gz |
setenv and unsetenv.
Diffstat (limited to 'lib/unsetenv.c')
-rw-r--r-- | lib/unsetenv.c | 104 |
1 files changed, 104 insertions, 0 deletions
diff --git a/lib/unsetenv.c b/lib/unsetenv.c new file mode 100644 index 0000000000..734589dce0 --- /dev/null +++ b/lib/unsetenv.c @@ -0,0 +1,104 @@ +/* Copyright (C) 1992,1995-1999,2000-2002 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Library General Public License as + published by the Free Software Foundation; either version 2 of the + License, or (at your option) any later version. + + The GNU C Library 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 + Library General Public License for more details. + + You should have received a copy of the GNU Library General Public + License along with the GNU C Library; see the file COPYING.LIB. If not, + write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, + Boston, MA 02111-1307, USA. */ + +#if HAVE_CONFIG_H +# include <config.h> +#endif + +#include <errno.h> +#if !_LIBC +# if !defined errno && !defined HAVE_ERRNO_DECL +extern int errno; +# endif +# define __set_errno(ev) ((errno) = (ev)) +#endif + +#if _LIBC || HAVE_STDLIB_H +# include <stdlib.h> +#endif +#if _LIBC || HAVE_STRING_H +# include <string.h> +#endif +#if _LIBC || HAVE_UNISTD_H +# include <unistd.h> +#endif + +#if !_LIBC +# define __environ environ +# ifndef HAVE_ENVIRON_DECL +extern char **environ; +# endif +#endif + +#if _LIBC +/* This lock protects against simultaneous modifications of `environ'. */ +# include <bits/libc-lock.h> +__libc_lock_define_initialized (static, envlock) +# define LOCK __libc_lock_lock (envlock) +# define UNLOCK __libc_lock_unlock (envlock) +#else +# define LOCK +# define UNLOCK +#endif + +/* In the GNU C library we must keep the namespace clean. */ +#ifdef _LIBC +# define unsetenv __unsetenv +#endif + + +int +unsetenv (const char *name) +{ + size_t len; + char **ep; + + if (name == NULL || *name == '\0' || strchr (name, '=') != NULL) + { + __set_errno (EINVAL); + return -1; + } + + len = strlen (name); + + LOCK; + + ep = __environ; + while (*ep != NULL) + if (!strncmp (*ep, name, len) && (*ep)[len] == '=') + { + /* Found it. Remove this pointer by moving later ones back. */ + char **dp = ep; + + do + dp[0] = dp[1]; + while (*dp++); + /* Continue the loop in case NAME appears again. */ + } + else + ++ep; + + UNLOCK; + + return 0; +} + +#ifdef _LIBC +# undef unsetenv +weak_alias (__unsetenv, unsetenv) +#endif |