glibc/csu/errno.c

/* Definition of `errno' variable.  Canonical version.
   Copyright (C) 2002-2023 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 Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 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
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <tls.h>
#include <dl-sysdep.h>
#undef errno

#if RTLD_PRIVATE_ERRNO

/* Code compiled for rtld refers only to this name.  */
int rtld_errno attribute_hidden;

#else

__thread int errno;
extern __thread int __libc_errno __attribute__ ((alias ("errno")))
  attribute_hidden;

#endif