lib/fbufmode.c

   1 /* Retrieve information about a FILE stream.
   2    Copyright (C) 2007-2025 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 "fbufmode.h"
  21
  22 #if HAVE___FLBF
  23 # if HAVE_STDIO_EXT_H
  24 #  include <stdio_ext.h>
  25 # endif
  26 #endif
  27
  28 #include "stdio-impl.h"
  29
  30 int
  31 fbufmode (FILE *fp)
  32 {
  33   /* Most systems provide FILE as a struct and the necessary bitmask in
  34      <stdio.h>, because they need it for implementing getc() and putc() as
  35      fast macros.  */
  36 #if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
  37   /* GNU libc, BeOS, Haiku, Linux libc5 */
  38 # if HAVE___FLBF                    /* glibc >= 2.2 */
  39   if (__flbf (fp))
  40     return _IOLBF;
  41 # else
  42   if (fp->_flags & _IO_LINE_BUF)
  43     return _IOLBF;
  44 # endif
  45   if (fp->_flags & _IO_UNBUFFERED)
  46     return _IONBF;
  47   return _IOFBF;
  48 #elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
  49   /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
  50   if (fp_->_flags & __SLBF)
  51     return _IOLBF;
  52   if (fp_->_flags & __SNBF)
  53     return _IONBF;
  54   return _IOFBF;
  55 #elif defined __EMX__               /* emx+gcc */
  56   return fp->_flags & (_IOLBF | _IONBF | _IOFBF);
  57 #elif defined __minix               /* Minix */
  58   return fp->_flags & (_IOLBF | _IONBF | _IOFBF);
  59 #elif defined _IOERR                /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
  60 # if defined WINDOWS_OPAQUE_FILE
  61   if (fp_->_flag & 0x100)
  62     return _IOFBF; /* Impossible to distinguish _IOFBF and _IOLBF.  */
  63   else
  64     return _IONBF;
  65 # else
  66 #  if HAVE___FLBF                   /* Solaris >= 7 */
  67   if (__flbf (fp))
  68     return _IOLBF;
  69 #  else
  70   if (fp_->_flag & _IOLBF)
  71     return _IOLBF;
  72 #  endif
  73   if (fp_->_flag & _IONBF)
  74     return _IONBF;
  75   return _IOFBF;
  76 # endif
  77 #elif defined __UCLIBC__            /* uClibc */
  78   if (fp->__modeflags & __FLAG_LBF)
  79     return _IOLBF;
  80   if (fp->__modeflags & __FLAG_NBF)
  81     return _IONBF;
  82   return _IOFBF;
  83 #elif defined __QNX__               /* QNX */
  84   if (fp->_Mode & 0x400 /* _MLBF */)
  85     return _IOLBF;
  86   if (fp->_Mode & 0x800 /* _MNBF */)
  87     return _IONBF;
  88   return _IOFBF;
  89 #elif defined __MINT__              /* Atari FreeMiNT */
  90   if (fp->__linebuf)
  91     return _IOLBF;
  92   return (fp->__bufsize > 0 ? _IOFBF : _IONBF);
  93 #elif HAVE___FLBF && HAVE___FBUFSIZE /* musl libc */
  94   if (__flbf (fp))
  95     return _IOLBF;
  96   return (__fbufsize (fp) > 0 ? _IOFBF : _IONBF);
  97 #elif defined EPLAN9                /* Plan9 */
  98   if (fp->flags & 2 /* LINEBUF */)
  99     return _IOLBF;
 100   if (fp->bufl)
 101     return _IOFBF;
 102   return _IONBF;
 103 #else
 104 # error "Please port gnulib fbufmode.c to your platform! Look at the setvbuf implementation."
 105 #endif
 106 }