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emacs/lib/fpending.c

64 lines
2.6 KiB
C

/* fpending.c -- return the number of pending output bytes on a stream
Copyright (C) 2000, 2004, 2006-2007, 2009-2021 Free Software Foundation,
Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* Written by Jim Meyering. */
#include <config.h>
/* Specification. */
#include "fpending.h"
#include "stdio-impl.h"
/* This file is not used on systems that already have the __fpending function,
namely glibc >= 2.2, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.34,
Android API >= 23. */
/* Return the number of pending (aka buffered, unflushed)
bytes on the stream, FP, that is open for writing. */
size_t
__fpending (FILE *fp)
{
/* Most systems provide FILE as a struct and the necessary bitmask in
<stdio.h>, because they need it for implementing getc() and putc() as
fast macros. */
#if defined _IO_EOF_SEEN || defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1
/* GNU libc, BeOS, Haiku, Linux libc5 */
return fp->_IO_write_ptr - fp->_IO_write_base;
#elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
/* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin < 1.7.34, Minix 3, Android */
return fp->_p - fp->_bf._base;
#elif defined __EMX__ /* emx+gcc */
return fp->_ptr - fp->_buffer;
#elif defined __minix /* Minix */
return fp_->_ptr - fp_->_buf;
#elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
return (fp_->_ptr ? fp_->_ptr - fp_->_base : 0);
#elif defined __UCLIBC__ /* uClibc */
return (fp->__modeflags & __FLAG_WRITING ? fp->__bufpos - fp->__bufstart : 0);
#elif defined __QNX__ /* QNX */
return (fp->_Mode & 0x2000 /*_MWRITE*/ ? fp->_Next - fp->_Buf : 0);
#elif defined __MINT__ /* Atari FreeMiNT */
return fp->__bufp - fp->__buffer;
#elif defined EPLAN9 /* Plan9 */
return fp->wp - fp->buf;
#else
# error "Please port gnulib fpending.c to your platform!"
return 1;
#endif
}