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[/] [openrisc/] [trunk/] [gnu-old/] [newlib-1.17.0/] [newlib/] [libc/] [stdio64/] [ftello64.c] - Rev 855
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/* * Copyright (c) 1990 The Regents of the University of California. * All rights reserved. * * Redistribution and use in source and binary forms are permitted * provided that the above copyright notice and this paragraph are * duplicated in all such forms and that any documentation, * advertising materials, and other materials related to such * distribution and use acknowledge that the software was developed * by the University of California, Berkeley. The name of the * University may not be used to endorse or promote products derived * from this software without specific prior written permission. * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. */ /* FUNCTION <<ftello64>>---return position in a stream or file INDEX ftello64 INDEX _ftello64_r ANSI_SYNOPSIS #include <stdio.h> _off64_t ftello64(FILE *<[fp]>); _off64_t _ftello64_r(struct _reent *<[ptr]>, FILE *<[fp]>); TRAD_SYNOPSIS #include <stdio.h> _off64_t ftello64(<[fp]>) FILE *<[fp]>; _off64_t _ftello64_r(<[ptr]>, <[fp]>) struct _reent *<[ptr]>; FILE *<[fp]>; DESCRIPTION Objects of type <<FILE>> can have a ``position'' that records how much of the file your program has already read. Many of the <<stdio>> functions depend on this position, and many change it as a side effect. The result of <<ftello64>> is the current position for a large file identified by <[fp]>. If you record this result, you can later use it with <<fseeko64>> to return the file to this position. The difference between <<ftello>> and <<ftello64>> is that <<ftello>> returns <<off_t>> and <<ftello64>> is designed to work for large files (>2GB) and returns <<_off64_t>>. In the current implementation, <<ftello64>> simply uses a character count to represent the file position; this is the same number that would be recorded by <<fgetpos64>>. The function exists only if the __LARGE64_FILES flag is defined. An error occurs if the <[fp]> was not opened via <<fopen64>>. RETURNS <<ftello64>> returns the file position, if possible. If it cannot do this, it returns <<-1>>. Failure occurs on streams that do not support positioning or not opened via <<fopen64>>; the global <<errno>> indicates this condition with the value <<ESPIPE>>. PORTABILITY <<ftello64>> is a glibc extension. No supporting OS subroutines are required. */ #if defined(LIBC_SCCS) && !defined(lint) static char sccsid[] = "%W% (Berkeley) %G%"; #endif /* LIBC_SCCS and not lint */ /* * ftello64: return current offset. */ #include <stdio.h> #include <errno.h> #include "local.h" #ifdef __LARGE64_FILES _off64_t _DEFUN (_ftello64_r, (ptr, fp), struct _reent *ptr _AND register FILE * fp) { _fpos64_t pos; /* Only do 64-bit tell on large file. */ if (!(fp->_flags & __SL64)) return (_off64_t) _ftello_r (ptr, fp); /* Ensure stdio is set up. */ CHECK_INIT (ptr, fp); _flockfile(fp); if (fp->_seek64 == NULL) { ptr->_errno = ESPIPE; _funlockfile(fp); return -1L; } /* Find offset of underlying I/O object, then adjust for buffered bytes. Flush a write stream, since the offset may be altered if the stream is appending. Do not flush a read stream, since we must not lose the ungetc buffer. */ if (fp->_flags & __SWR) _fflush_r (ptr, fp); if (fp->_flags & __SOFF) pos = fp->_offset; else { pos = fp->_seek64 (ptr, fp->_cookie, (_fpos64_t) 0, SEEK_CUR); if (pos == -1L) { _funlockfile(fp); return pos; } } if (fp->_flags & __SRD) { /* * Reading. Any unread characters (including * those from ungetc) cause the position to be * smaller than that in the underlying object. */ pos -= fp->_r; if (HASUB (fp)) pos -= fp->_ur; } else if (fp->_flags & __SWR && fp->_p != NULL) { /* * Writing. Any buffered characters cause the * position to be greater than that in the * underlying object. */ pos += fp->_p - fp->_bf._base; } _funlockfile(fp); return pos; } #ifndef _REENT_ONLY _off64_t _DEFUN (ftello64, (fp), register FILE * fp) { return _ftello64_r (_REENT, fp); } #endif /* !_REENT_ONLY */ #endif /* __LARGE64_FILES */
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