1  /* Copyright (C) 1993-2023 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  #include "libioP.h"
      19  #include <wchar.h>
      20  #include <sys/param.h>
      21  
      22  wchar_t *
      23  __fgetws_chk (wchar_t *buf, size_t size, int n, FILE *fp)
      24  {
      25    size_t count;
      26    wchar_t *result;
      27    int old_error;
      28    CHECK_FILE (fp, NULL);
      29    if (n <= 0)
      30      return NULL;
      31    _IO_acquire_lock (fp);
      32    /* This is very tricky since a file descriptor may be in the
      33       non-blocking mode. The error flag doesn't mean much in this
      34       case. We return an error only when there is a new error. */
      35    old_error = fp->_flags & _IO_ERR_SEEN;
      36    fp->_flags &= ~_IO_ERR_SEEN;
      37    count = _IO_getwline (fp, buf, MIN ((size_t) n - 1, size), L'\n', 1);
      38    /* If we read in some bytes and errno is EAGAIN, that error will
      39       be reported for next read. */
      40    if (count == 0 || (_IO_ferror_unlocked (fp) && errno != EAGAIN))
      41      result = NULL;
      42    else if (count >= size)
      43      __chk_fail ();
      44    else
      45      {
      46        buf[count] = '\0';
      47        result = buf;
      48      }
      49    fp->_flags |= old_error;
      50    _IO_release_lock (fp);
      51    return result;
      52  }