text: /* An ftello() function that works around platform bugs.
     Copyright (C) 2007, 2009-2016 Free Software Foundation, Inc.
  
     This program is free software: you can redistribute it and/or modify
     it under the terms of the GNU Lesser General Public License as published by
     the Free Software Foundation; either version 2.1 of the License, or
     (at your option) any later version.
  
     This program is distributed in the hope that it will be useful,
     but WITHOUT ANY WARRANTY; without even the implied warranty of
     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
     GNU Lesser General Public License for more details.
  
     You should have received a copy of the GNU Lesser General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  
  #include <config.h>
  
  /* Specification.  */
  #include <stdio.h>
  
  /* Get lseek.  */
  #include <unistd.h>
  
  #include "stdio-impl.h"
  
  off_t
  ftello (FILE *fp)
  #undef ftello
  #if !HAVE_FTELLO
  # undef ftell
  # define ftello ftell
  #endif
  #if _GL_WINDOWS_64_BIT_OFF_T
  # undef ftello
  # if HAVE__FTELLI64 /* msvc, mingw64 */
  #  define ftello _ftelli64
  # else /* mingw */
  #  define ftello ftello64
  # endif
  #endif
  {
  #if LSEEK_PIPE_BROKEN
    /* mingw gives bogus answers rather than failure on non-seekable files.  */
    if (lseek (fileno (fp), 0, SEEK_CUR) == -1)
      return -1;
  #endif
  
  #if FTELLO_BROKEN_AFTER_SWITCHING_FROM_READ_TO_WRITE /* Solaris */
    /* The Solaris stdio leaves the _IOREAD flag set after reading from a file
       reaches EOF and the program then starts writing to the file.  ftello
       gets confused by this.  */
    if (fp_->_flag & _IOWRT)
      {
        off_t pos;
  
        /* Call ftello nevertheless, for the side effects that it does on fp.  */
        ftello (fp);
  
        /* Compute the file position ourselves.  */
        pos = lseek (fileno (fp), (off_t) 0, SEEK_CUR);
        if (pos >= 0)
          {
            if ((fp_->_flag & _IONBF) == 0 && fp_->_base != NULL)
              pos += fp_->_ptr - fp_->_base;
          }
        return pos;
      }
  #endif
  
  #if defined __SL64 && defined __SCLE /* Cygwin */
    if ((fp->_flags & __SL64) == 0)
      {
        /* Cygwin 1.5.0 through 1.5.24 failed to open stdin in 64-bit
           mode; but has an ftello that requires 64-bit mode.  */
        FILE *tmp = fopen ("/dev/null", "r");
        if (!tmp)
          return -1;
        fp->_flags |= __SL64;
        fp->_seek64 = tmp->_seek64;
        fclose (tmp);
      }
  #endif
    return ftello (fp);
  }
  