2fe8fb192f
There is important information about booting non-ack images in docs/UPDATING. ack/aout-format images can't be built any more, and booting clang/ELF-format ones is a little different. Updating to the new boot monitor is recommended. Changes in this commit: . drop boot monitor -> allowing dropping ack support . facility to copy ELF boot files to /boot so that old boot monitor can still boot fairly easily, see UPDATING . no more ack-format libraries -> single-case libraries . some cleanup of OBJECT_FMT, COMPILER_TYPE, etc cases . drop several ack toolchain commands, but not all support commands (e.g. aal is gone but acksize is not yet). . a few libc files moved to netbsd libc dir . new /bin/date as minix date used code in libc/ . test compile fix . harmonize includes . /usr/lib is no longer special: without ack, /usr/lib plays no kind of special bootstrapping role any more and bootstrapping is done exclusively through packages, so releases depend even less on the state of the machine making them now. . rename nbsd_lib* to lib* . reduce mtree
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5.5 KiB
Groff
251 lines
5.5 KiB
Groff
.\" $NetBSD: fseek.3,v 1.25 2010/10/22 21:29:31 christos Exp $
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.\"
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.\" Copyright (c) 1990, 1991, 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" This code is derived from software contributed to Berkeley by
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.\" Chris Torek and the American National Standards Committee X3,
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.\" on Information Processing Systems.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\" 3. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\"
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.\" @(#)fseek.3 8.1 (Berkeley) 6/4/93
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.\"
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.Dd October 22, 2010
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.Dt FSEEK 3
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.Os
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.Sh NAME
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.Nm fgetpos ,
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.Nm fseek ,
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.Nm fseeko ,
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.Nm fsetpos ,
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.Nm ftell ,
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.Nm ftello ,
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.Nm rewind
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.Nd reposition a stream
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.In stdio.h
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.Ft int
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.Fn fseek "FILE *stream" "long int offset" "int whence"
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.Ft int
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.Fn fseeko "FILE *stream" "off_t offset" "int whence"
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.Ft long int
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.Fn ftell "FILE *stream"
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.Ft off_t
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.Fn ftello "FILE *stream"
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.Ft void
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.Fn rewind "FILE *stream"
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.Ft int
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.Fn fgetpos "FILE * restrict stream" "fpos_t * restrict pos"
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.Ft int
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.Fn fsetpos "FILE * restrict stream" "const fpos_t * restrict pos"
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.Sh DESCRIPTION
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The
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.Fn fseek
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function sets the file position indicator for the stream pointed
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to by
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.Fa stream .
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The new position, measured in bytes, is obtained by adding
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.Fa offset
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bytes to the position specified by
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.Fa whence .
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If
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.Fa whence
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is set to
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.Dv SEEK_SET ,
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.Dv SEEK_CUR ,
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or
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.Dv SEEK_END ,
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the offset is relative to the
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start of the file, the current position indicator, or end-of-file,
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respectively.
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A successful call to the
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.Fn fseek
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function clears the end-of-file indicator for the stream and undoes
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any effects of the
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.Xr ungetc 3
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function on the same stream.
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.Pp
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The
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.Fn fseeko
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function is identical to the
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.Fn fseek
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function except that the
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.Fa offset
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argument is of type
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.Fa off_t .
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.Pp
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The
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.Fn ftell
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function
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obtains the current value of the file position indicator for the
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stream pointed to by
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.Fa stream .
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.Pp
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The
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.Fn ftello
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function is identical to the
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.Fn ftell
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function except that the return value is of type
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.Fa off_t .
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.Pp
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The
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.Fn rewind
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function sets the file position indicator for the stream pointed
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to by
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.Fa stream
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to the beginning of the file.
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It is equivalent to:
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.Pp
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.Dl (void)fseek(stream, 0L, SEEK_SET)
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.Pp
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except that the error indicator for the stream is also cleared
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(see
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.Xr clearerr 3 ) .
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.Pp
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In this implementation, the
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.Fn fgetpos
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and
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.Fn fsetpos
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functions
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are alternative interfaces equivalent to
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.Fn ftell ,
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.Fn ftello ,
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.Fn fseek ,
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and
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.Fn fseeko
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(with whence set to
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.Dv SEEK_SET ) ,
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setting and storing the current value of
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the file offset into or from the object referenced by
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.Fa pos .
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In others implementations, an
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.Dq Fa fpos_t
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object may be a complex object
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and these routines may be the only way to portably reposition a text stream.
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.Sh RETURN VALUES
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The
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.Fn rewind
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function
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returns no value.
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Upon successful completion,
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.Fn fgetpos ,
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.Fn fseek ,
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.Fn fseeko ,
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and
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.Fn fsetpos
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return 0.
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The functions
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.Fn ftell
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and
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.Fn ftello
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return the current offset.
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Otherwise,
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.Fn fseek ,
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.Fn fseeko ,
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.Fn ftell ,
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and
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.Fn ftello
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return \-1 while
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.Fn fgetpos
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and
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.Fn fsetpos
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return a nonzero value.
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On error all functions the global variable
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.Va errno
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is set to indicate the error.
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Since the
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.Fn rewind
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function does not return an error code, applications need to clear
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.Va errno
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before calling it in order to detect errors.
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.Sh ERRORS
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.Bl -tag -width Er
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.It Bq Er EBADF
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The
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.Fa stream
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specified
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is not a seekable stream.
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.It Bq Er EINVAL
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The
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.Fa whence
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argument to
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.Fn fseek
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was not
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.Dv SEEK_SET ,
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.Dv SEEK_END ,
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or
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.Dv SEEK_CUR .
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.It Bq Er EOVERFLOW
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For
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.Fn ftell ,
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the current file offset cannot be represented correctly in an object of type
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.Fa long .
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.El
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.Pp
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The function
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.Fn fgetpos ,
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.Fn fseek ,
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.Fn fseeko ,
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.Fn fsetpos ,
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.Fn ftell ,
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.Fn ftello ,
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and
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.Fn rewind
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may also fail and set
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.Va errno
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for any of the errors specified for the routines
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.Xr fflush 3 ,
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.Xr fstat 2 ,
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.Xr lseek 2 ,
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and
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.Xr malloc 3 .
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.Sh SEE ALSO
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.Xr lseek 2
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.Sh STANDARDS
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The
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.Fn fgetpos ,
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.Fn fsetpos ,
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.Fn fseek ,
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.Fn ftell ,
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and
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.Fn rewind
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functions
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conform to
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.St -ansiC .
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The
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.Fn fseeko
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and
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.Fn ftello
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functions conform to
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.St -xsh5 .
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.Sh BUGS
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The
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.Fn fgetpos
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and
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.Fn fsetpos
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functions don't store/set shift states of the stream in this implementation.
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