1  /* Error constants.  Generic version.
       2     Copyright (C) 1991-2023 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.  */