bits/errno.h

   1 /* Error constants.  Generic version.
   2    Copyright (C) 1991-2021 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 /* This file defines the errno constants.  */
  20
  21 #ifndef _BITS_ERRNO_H
  22 #define _BITS_ERRNO_H 1
  23
  24 #if !defined _ERRNO_H
  25 # error "Never include <bits/errno.h> directly; use <errno.h> instead."
  26 #endif
  27
  28 #error "Generic bits/errno.h included -- port is incomplete."
  29
  30 /* Authors of new ports of the GNU C Library must override this file
  31    with their own bits/errno.h in an appropriate subdirectory of
  32    sysdeps/.  Its function is to define all of the error constants
  33    from C2011 and POSIX.1-2008, with values appropriate to the
  34    operating system, and any additional OS-specific error constants.
  35
  36    C2011 requires all error constants to be object-like macros that
  37    expand to "integer constant expressions with type int, positive
  38    values, and suitable for use in #if directives".  Moreover, all of
  39    their names must begin with a capital E, followed immediately by
  40    either another capital letter, or a digit.  It is OK to define
  41    macros that are not error constants, but only in the implementation
  42    namespace.
  43
  44    errno.h is sometimes included from assembly language.  Therefore,
  45    when __ASSEMBLER__ is defined, bits/errno.h may only define macros;
  46    it may not make any other kind of C declaration or definition.
  47    Also, the error constants should, if at all possible, expand to
  48    simple decimal or hexadecimal numbers.  */
  49
  50 #endif /* bits/errno.h.  */