1 /* An fseeko() function that, together with fflush(), is POSIX compliant.
2 Copyright (C) 2007-2009 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation; either version 2, or (at your option)
9 This program 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 General Public License for more details.
14 You should have received a copy of the GNU General Public License along
15 with this program; if not, write to the Free Software Foundation,
16 Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
23 /* Get off_t and lseek. */
26 #include "stdio-impl.h"
35 rpl_fseeko (FILE *fp, off_t offset, int whence)
38 /* mingw gives bogus answers rather than failure on non-seekable files. */
39 if (lseek (fileno (fp), 0, SEEK_CUR) == -1)
43 /* These tests are based on fpurge.c. */
44 #if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
45 if (fp->_IO_read_end == fp->_IO_read_ptr
46 && fp->_IO_write_ptr == fp->_IO_write_base
47 && fp->_IO_save_base == NULL)
48 #elif defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */
49 # if defined __SL64 && defined __SCLE /* Cygwin */
50 if ((fp->_flags & __SL64) == 0)
52 /* Cygwin 1.5.0 through 1.5.24 failed to open stdin in 64-bit
53 mode; but has an fseeko that requires 64-bit mode. */
54 FILE *tmp = fopen ("/dev/null", "r");
58 fp->_seek64 = tmp->_seek64;
62 if (fp_->_p == fp_->_bf._base
64 && fp_->_w == ((fp_->_flags & (__SLBF | __SNBF | __SRD)) == 0 /* fully buffered and not currently reading? */
67 && fp_ub._base == NULL)
68 #elif defined __EMX__ /* emx+gcc */
69 if (fp->_ptr == fp->_buffer
72 && fp->_ungetc_count == 0)
73 #elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, mingw */
74 if (fp_->_ptr == fp_->_base
75 && (fp_->_ptr == NULL || fp_->_cnt == 0))
76 #elif defined __UCLIBC__ /* uClibc */
77 if (((fp->__modeflags & __FLAG_WRITING) == 0
78 || fp->__bufpos == fp->__bufstart)
79 && ((fp->__modeflags & (__FLAG_READONLY | __FLAG_READING)) == 0
80 || fp->__bufpos == fp->__bufread))
81 #elif defined __QNX__ /* QNX */
82 if ((fp->_Mode & _MWRITE ? fp->_Next == fp->_Buf : fp->_Next == fp->_Rend)
83 && fp->_Rback == fp->_Back + sizeof (fp->_Back)
84 && fp->_Rsave == NULL)
86 #error "Please port gnulib fseeko.c to your platform! Look at the code in fpurge.c, then report this to bug-gnulib."
89 /* We get here when an fflush() call immediately preceded this one. We
90 know there are no buffers.
91 POSIX requires us to modify the file descriptor's position.
92 But we cannot position beyond end of file here. */
95 whence == SEEK_END && offset > 0 ? 0 : offset,
99 #if defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */
100 fp_->_flags &= ~__SOFF;
105 #if defined _IO_ftrylockfile || __GNU_LIBRARY__ == 1 /* GNU libc, BeOS, Haiku, Linux libc5 */
106 fp->_flags &= ~_IO_EOF_SEEN;
107 #elif defined __sferror || defined __DragonFly__ /* FreeBSD, NetBSD, OpenBSD, DragonFly, MacOS X, Cygwin */
109 fp_->_flags |= __SOFF;
110 fp_->_flags &= ~__SEOF;
111 #elif defined __EMX__ /* emx+gcc */
112 fp->_flags &= ~_IOEOF;
113 #elif defined _IOERR /* AIX, HP-UX, IRIX, OSF/1, Solaris, OpenServer, mingw */
114 fp->_flag &= ~_IOEOF;
116 /* If we were not requested to position beyond end of file, we're
118 if (!(whence == SEEK_END && offset > 0))
121 return fseeko (fp, offset, whence);