1  /* Internal errno names mapping definition.
       2     Copyright (C) 2022-2023 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  #include <stdio.h>
      20  #include <errno.h>
      21  #include <libintl.h>
      22  #include <array_length.h>
      23  
      24  #ifndef ERR_MAP
      25  # define ERR_MAP(n) n
      26  #endif
      27  
      28  static const union sys_errname_t
      29  {
      30    struct
      31    {
      32  #define MSGSTRFIELD1(line) str##line
      33  #define MSGSTRFIELD(line)  MSGSTRFIELD1(line)
      34  #define _S(n, str)         char MSGSTRFIELD(__LINE__)[sizeof(#n)];
      35  #include <errlist.h>
      36  #undef _S
      37    };
      38    char str[0];
      39  } _sys_errname = { {
      40  #define _S(n, s) #n,
      41  #include <errlist.h>
      42  #undef _S
      43  } };
      44  
      45  static const unsigned short _sys_errnameidx[] =
      46  {
      47  #define _S(n, s) \
      48    [ERR_MAP(n)] = offsetof(union sys_errname_t, MSGSTRFIELD(__LINE__)),
      49  #include <errlist.h>
      50  #undef _S
      51  };
      52  
      53  const char *
      54  __get_errname (int errnum)
      55  {
      56    int mapped = ERR_MAP (errnum);
      57    if (mapped < 0 || mapped >= array_length (_sys_errnameidx)
      58        || (mapped > 0 && _sys_errnameidx[mapped] == 0))
      59      return NULL;
      60    return _sys_errname.str + _sys_errnameidx[mapped];
      61  }