1  /* Retrieve information about a FILE stream.
       2     Copyright (C) 2007-2023 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 2.1 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 "freading.h"
      21  
      22  #include "stdio-impl.h"
      23  
      24  /* Don't use glibc's __freading function in glibc < 2.7, see
      25     <https://sourceware.org/bugzilla/show_bug.cgi?id=4359>  */
      26  #if !(HAVE___FREADING && (!defined __GLIBC__ || defined __UCLIBC__ || __GLIBC__ > 2 || (__GLIBC__ == 2 && __GLIBC_MINOR__ >= 7)))
      27  
      28  bool
      29  freading (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_WRITES) != 0
      37            || ((fp->_flags & (_IO_NO_READS | _IO_CURRENTLY_PUTTING)) == 0
      38                && fp->_IO_read_base != NULL));
      39  # elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
      40    /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin < 1.7.34, Minix 3, Android */
      41    return (fp_->_flags & __SRD) != 0;
      42  # elif defined __EMX__               /* emx+gcc */
      43    return (fp->_flags & _IOREAD) != 0;
      44  # elif defined __minix               /* Minix */
      45    return (fp->_flags & _IOREADING) != 0;
      46  # elif defined _IOERR                /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
      47  #  if defined __sun                  /* Solaris */
      48    return (fp_->_flag & _IOREAD) != 0 && (fp_->_flag & _IOWRT) == 0;
      49  #  else
      50    return (fp_->_flag & _IOREAD) != 0;
      51  #  endif
      52  # elif defined __UCLIBC__            /* uClibc */
      53    return (fp->__modeflags & (__FLAG_READONLY | __FLAG_READING)) != 0;
      54  # elif defined __QNX__               /* QNX */
      55    return ((fp->_Mode & 0x2 /* _MOPENW */) == 0
      56            || (fp->_Mode & 0x1000 /* _MREAD */) != 0);
      57  # elif defined __MINT__              /* Atari FreeMiNT */
      58    if (!fp->__mode.__write)
      59      return 1;
      60    if (!fp->__mode.__read)
      61      return 0;
      62  #  ifdef _IO_CURRENTLY_GETTING /* Flag added on 2009-02-28 */
      63    return (fp->__flags & _IO_CURRENTLY_GETTING) != 0;
      64  #  else
      65    return (fp->__buffer < fp->__get_limit /*|| fp->__bufp == fp->__put_limit ??*/);
      66  #  endif
      67  # elif defined EPLAN9                /* Plan9 */
      68    if (fp->state == 0 /* CLOSED */ || fp->state == 4 /* WR */)
      69      return 0;
      70    return (fp->state == 3 /* RD */ && (fp->bufl == 0 || fp->rp < fp->wp));
      71  # else
      72  #  error "Please port gnulib freading.c to your platform!"
      73  # endif
      74  }
      75  
      76  #endif