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diff --git a/lib/fpurge.c b/lib/fpurge.c
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+/* Flushing buffers of a FILE stream.
+ Copyright (C) 2007-2022 Free Software Foundation, Inc.
+
+ This file is free software: you can redistribute it and/or modify
+ it under the terms of the GNU Lesser General Public License as
+ published by the Free Software Foundation; either version 2.1 of the
+ License, or (at your option) any later version.
+
+ This file 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 Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public License
+ along with this program. If not, see <https://www.gnu.org/licenses/>. */
+
+#include <config.h>
+
+/* Specification. */
+#include <stdio.h>
+
+#if HAVE___FPURGE /* glibc >= 2.2, Haiku, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.10, Android API >= 23, musl libc */
+# if HAVE_STDIO_EXT_H
+# include <stdio_ext.h>
+# endif
+#endif
+#include <stdlib.h>
+
+#include "stdio-impl.h"
+
+int
+fpurge (FILE *fp)
+{
+#if HAVE___FPURGE /* glibc >= 2.2, Haiku, Solaris >= 7, UnixWare >= 7.1.4.MP4, Cygwin >= 1.7.10, Android API >= 23, musl libc */
+
+ __fpurge (fp);
+ /* The __fpurge function does not have a return value. */
+ return 0;
+
+#elif HAVE_FPURGE /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin >= 1.7 */
+
+ /* Call the system's fpurge function. */
+# undef fpurge
+# if !HAVE_DECL_FPURGE
+ extern int fpurge (FILE *);
+# endif
+ int result = fpurge (fp);
+# if defined __sferror || defined __DragonFly__ || defined __ANDROID__
+ /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
+ if (result == 0)
+ /* Correct the invariants that fpurge broke.
+ <stdio.h> on BSD systems says:
+ "The following always hold: if _flags & __SRD, _w is 0."
+ If this invariant is not fulfilled and the stream is read-write but
+ currently reading, subsequent putc or fputc calls will write directly
+ into the buffer, although they shouldn't be allowed to. */
+ if ((fp_->_flags & __SRD) != 0)
+ fp_->_w = 0;
+# endif
+ return result;
+
+#else
+
+ /* 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 */
+ fp->_IO_read_end = fp->_IO_read_ptr;
+ fp->_IO_write_ptr = fp->_IO_write_base;
+ /* Avoid memory leak when there is an active ungetc buffer. */
+ if (fp->_IO_save_base != NULL)
+ {
+ free (fp->_IO_save_base);
+ fp->_IO_save_base = NULL;
+ }
+ return 0;
+# elif defined __sferror || defined __DragonFly__ || defined __ANDROID__
+ /* FreeBSD, NetBSD, OpenBSD, DragonFly, Mac OS X, Cygwin, Minix 3, Android */
+ fp_->_p = fp_->_bf._base;
+ fp_->_r = 0;
+ fp_->_w = ((fp_->_flags & (__SLBF | __SNBF | __SRD)) == 0 /* fully buffered and not currently reading? */
+ ? fp_->_bf._size
+ : 0);
+ /* Avoid memory leak when there is an active ungetc buffer. */
+ if (fp_ub._base != NULL)
+ {
+ if (fp_ub._base != fp_->_ubuf)
+ free (fp_ub._base);
+ fp_ub._base = NULL;
+ }
+ return 0;
+# elif defined __EMX__ /* emx+gcc */
+ fp->_ptr = fp->_buffer;
+ fp->_rcount = 0;
+ fp->_wcount = 0;
+ fp->_ungetc_count = 0;
+ return 0;
+# elif defined __minix /* Minix */
+ fp->_ptr = fp->_buf;
+ if (fp->_ptr != NULL)
+ fp->_count = 0;
+ return 0;
+# elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, UnixWare, mingw, MSVC, NonStop Kernel, OpenVMS */
+ fp_->_ptr = fp_->_base;
+ if (fp_->_ptr != NULL)
+ fp_->_cnt = 0;
+ return 0;
+# elif defined __UCLIBC__ /* uClibc */
+# ifdef __STDIO_BUFFERS
+ if (fp->__modeflags & __FLAG_WRITING)
+ fp->__bufpos = fp->__bufstart;
+ else if (fp->__modeflags & (__FLAG_READONLY | __FLAG_READING))
+ fp->__bufpos = fp->__bufread;
+# endif
+ return 0;
+# elif defined __QNX__ /* QNX */
+ fp->_Rback = fp->_Back + sizeof (fp->_Back);
+ fp->_Rsave = NULL;
+ if (fp->_Mode & 0x2000 /* _MWRITE */)
+ /* fp->_Buf <= fp->_Next <= fp->_Wend */
+ fp->_Next = fp->_Buf;
+ else
+ /* fp->_Buf <= fp->_Next <= fp->_Rend */
+ fp->_Rend = fp->_Next;
+ return 0;
+# elif defined __MINT__ /* Atari FreeMiNT */
+ if (fp->__pushed_back)
+ {
+ fp->__bufp = fp->__pushback_bufp;
+ fp->__pushed_back = 0;
+ }
+ /* Preserve the current file position. */
+ if (fp->__target != -1)
+ fp->__target += fp->__bufp - fp->__buffer;
+ fp->__bufp = fp->__buffer;
+ /* Nothing in the buffer, next getc is nontrivial. */
+ fp->__get_limit = fp->__bufp;
+ /* Nothing in the buffer, next putc is nontrivial. */
+ fp->__put_limit = fp->__buffer;
+ return 0;
+# elif defined EPLAN9 /* Plan9 */
+ fp->rp = fp->wp = fp->lp = fp->buf;
+ return 0;
+# else
+# error "Please port gnulib fpurge.c to your platform! Look at the definitions of fflush, setvbuf and ungetc on your system, then report this to bug-gnulib."
+# endif
+
+#endif
+}