1  /* fpending.c -- return the number of pending output bytes on a stream
       2     Copyright (C) 2000, 2004, 2006-2007, 2009-2023 Free Software Foundation,
       3     Inc.
       4  
       5     This program is free software: you can redistribute it and/or modify
       6     it under the terms of the GNU General Public License as published by
       7     the Free Software Foundation, either version 3 of the License, or
       8     (at your option) any later version.
       9  
      10     This program 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
      13     GNU General Public License for more details.
      14  
      15     You should have received a copy of the GNU General Public License
      16     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      17  
      18  /* Written by Jim Meyering. */
      19  
      20  #include <config.h>
      21  
      22  /* Specification.  */
      23  #include "fpending.h"
      24  
      25  #include "stdio-impl.h"
      26  
      27  /* This file is not used on systems that already have the __fpending function,
      28     namely glibc >= 2.2, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.34,
      29     Android API >= 23.  */
      30  
      31  /* Return the number of pending (aka buffered, unflushed)
      32     bytes on the stream, FP, that is open for writing.  */
      33  size_t
      34  __fpending (FILE *fp)
      35  {
      36    /* Most systems provide FILE as a struct and the necessary bitmask in
      37       <stdio.h>, because they need it for implementing getc() and putc() as
      38       fast macros.  */
      39  #if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
      40    /* GNU libc, BeOS, Haiku, Linux libc5 */
      41    return fp->_IO_write_ptr - fp->_IO_write_base;
      42  #elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
      43    /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin < 1.7.34, Minix 3, Android */
      44    return fp_->_p - fp_->_bf._base;
      45  #elif defined __EMX__                /* emx+gcc */
      46    return fp->_ptr - fp->_buffer;
      47  #elif defined __minix                /* Minix */
      48    return fp_->_ptr - fp_->_buf;
      49  #elif defined _IOERR                 /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
      50    return (fp_->_ptr ? fp_->_ptr - fp_->_base : 0);
      51  #elif defined __UCLIBC__             /* uClibc */
      52    return (fp->__modeflags & __FLAG_WRITING ? fp->__bufpos - fp->__bufstart : 0);
      53  #elif defined __QNX__                /* QNX */
      54    return (fp->_Mode & 0x2000 /*_MWRITE*/ ? fp->_Next - fp->_Buf : 0);
      55  #elif defined __MINT__               /* Atari FreeMiNT */
      56    return fp->__bufp - fp->__buffer;
      57  #elif defined EPLAN9                 /* Plan9 */
      58    return fp->wp - fp->buf;
      59  #else
      60  # error "Please port gnulib fpending.c to your platform!"
      61    return 1;
      62  #endif
      63  }