libio/vswprintf.c

   1 /* Copyright (C) 1994-2023 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <https://www.gnu.org/licenses/>.
  17
  18    As a special exception, if you link the code in this file with
  19    files compiled with a GNU compiler to produce an executable,
  20    that does not cause the resulting executable to be covered by
  21    the GNU Lesser General Public License.  This exception does not
  22    however invalidate any other reasons why the executable file
  23    might be covered by the GNU Lesser General Public License.
  24    This exception applies to code released by its copyright holders
  25    in files containing the exception.  */
  26
  27 #include <errno.h>
  28 #include <math_ldbl_opt.h>
  29 #include <printf.h>
  30 #include <printf_buffer.h>
  31
  32 int
  33 __vswprintf_internal (wchar_t *string, size_t maxlen, const wchar_t *format,
  34                       va_list args, unsigned int mode_flags)
  35 {
  36   if (maxlen == 0)
  37     /* Since we have to write at least the terminating L'\0' a buffer
  38        length of zero always makes the function fail.  */
  39     return -1;
  40
  41   struct __wprintf_buffer buf;
  42   __wprintf_buffer_init (&buf, string, maxlen, __wprintf_buffer_mode_swprintf);
  43
  44   __wprintf_buffer (&buf, format, args, mode_flags);
  45
  46   if (buf.write_ptr == buf.write_end)
  47     {
  48       /* Buffer has been filled exactly, excluding the null wide
  49          character.  This is an error because the null wide character
  50          is required.  */
  51       buf.write_end[-1] = L'\0';
  52       return -1;
  53     }
  54
  55   buf.write_ptr[0] = L'\0';
  56
  57   return __wprintf_buffer_done (&buf);
  58 }
  59
  60 int
  61 __vswprintf (wchar_t *string, size_t maxlen, const wchar_t *format,
  62              va_list args)
  63 {
  64   return __vswprintf_internal (string, maxlen, format, args, 0);
  65 }
  66 ldbl_weak_alias (__vswprintf, vswprintf)