1  /* Retrieve information about a FILE stream.
       2     Copyright (C) 2007-2022 Free Software Foundation, Inc.
       3  
       4     This file is free software: you can redistribute it and/or modify
       5     it under the terms of the GNU Lesser General Public License as
       6     published by the Free Software Foundation, either version 3 of the
       7     License, or (at your option) any later version.
       8  
       9     This file 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
      12     GNU Lesser General Public License for more details.
      13  
      14     You should have received a copy of the GNU Lesser General Public License
      15     along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
      16  
      17  #include <config.h>
      18  
      19  /* Specification.  */
      20  #include "fwriting.h"
      21  
      22  #include "stdio-impl.h"
      23  
      24  /* This file is not used on systems that have the __fwriting function,
      25     namely glibc >= 2.2, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.34,
      26     Android API >= 29, musl libc.  */
      27  
      28  bool
      29  fwriting (FILE *fp)
      30  {
      31    /* Most systems provide FILE as a struct and the necessary bitmask in
      32       <stdio.h>, because they need it for implementing getc() and putc() as
      33       fast macros.  */
      34  #if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
      35    /* GNU libc, BeOS, Haiku, Linux libc5 */
      36    return (fp->_flags & (_IO_NO_READS | _IO_CURRENTLY_PUTTING)) != 0;
      37  #elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
      38    /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin < 1.7.34, Minix 3, Android */
      39    return (fp_->_flags & __SWR) != 0;
      40  #elif defined __EMX__               /* emx+gcc */
      41    return (fp->_flags & _IOWRT) != 0;
      42  #elif defined __minix               /* Minix */
      43    return (fp->_flags & _IOWRITING) != 0;
      44  #elif defined _IOERR                /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
      45    return (fp_->_flag & _IOWRT) != 0;
      46  #elif defined __UCLIBC__            /* uClibc */
      47    return (fp->__modeflags & __FLAG_WRITING) != 0;
      48  #elif defined __QNX__               /* QNX */
      49    return ((fp->_Mode & 0x1 /* _MOPENR */) == 0
      50            || (fp->_Mode & 0x2000 /* _MWRITE */) != 0);
      51  #elif defined __MINT__              /* Atari FreeMiNT */
      52    if (!fp->__mode.__read)
      53      return 1;
      54    if (!fp->__mode.__write)
      55      return 0;
      56  # ifdef _IO_CURRENTLY_PUTTING /* Flag added on 2009-02-28 */
      57    return (fp->__flags & _IO_CURRENTLY_PUTTING) != 0;
      58  # else
      59    return (fp->__buffer < fp->__put_limit /*|| fp->__bufp == fp->__get_limit ??*/);
      60  # endif
      61  #elif defined EPLAN9                /* Plan9 */
      62    if (fp->state == 0 /* CLOSED */ || fp->state == 3 /* RD */)
      63      return 0;
      64    return (fp->state == 4 /* WR */ && (fp->bufl == 0 || fp->wp < fp->rp));
      65  #else
      66  # error "Please port gnulib fwriting.c to your platform!"
      67  #endif
      68  }