'\" et
.TH FTELL "3P" 2017 "IEEE/The Open Group" "POSIX Programmer's Manual"
.\"
.SH PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
.\"
.SH NAME
ftell,
ftello
\(em return a file offset in a stream
.SH SYNOPSIS
.LP
.nf
#include <stdio.h>
.P
long ftell(FILE *\fIstream\fP);
off_t ftello(FILE *\fIstream\fP);
.fi
.SH DESCRIPTION
The functionality described on this reference page is aligned with the
ISO\ C standard. Any conflict between the requirements described here and the
ISO\ C standard is unintentional. This volume of POSIX.1\(hy2017 defers to the ISO\ C standard.
.P
The
\fIftell\fR()
function shall obtain the current value of the file-position indicator
for the stream pointed to by
.IR stream .
.P
The
\fIftell\fR()
function shall not change the setting of
.IR errno
if successful.
.P
The
\fIftello\fR()
function shall be equivalent to
\fIftell\fR(),
except that the return value is of type
.BR off_t
and the
\fIftello\fR()
function may change the setting of
.IR errno
if successful.
.SH "RETURN VALUE"
Upon successful completion,
\fIftell\fR()
and
\fIftello\fR()
shall return the current value of the file-position indicator for the
stream measured in bytes from the beginning of the file.
.P
Otherwise,
\fIftell\fR()
and
\fIftello\fR()
shall return \-1, and set
.IR errno
to indicate the error.
.SH ERRORS
The
\fIftell\fR()
and
\fIftello\fR()
functions shall fail if:
.TP
.BR EBADF
The file descriptor underlying
.IR stream
is not an open file descriptor.
.TP
.BR EOVERFLOW
For
\fIftell\fR(),
the current file offset cannot be represented correctly in an object of
type
.BR long .
.TP
.BR EOVERFLOW
For
\fIftello\fR(),
the current file offset cannot be represented correctly in an object of
type
.BR off_t .
.TP
.BR ESPIPE
The file descriptor underlying
.IR stream
is associated with a pipe, FIFO, or socket.
.LP
.IR "The following sections are informative."
.SH EXAMPLES
None.
.SH "APPLICATION USAGE"
None.
.SH RATIONALE
None.
.SH "FUTURE DIRECTIONS"
None.
.SH "SEE ALSO"
.IR "Section 2.5" ", " "Standard I/O Streams",
.IR "\fIfgetpos\fR\^(\|)",
.IR "\fIfopen\fR\^(\|)",
.IR "\fIfseek\fR\^(\|)",
.IR "\fIlseek\fR\^(\|)"
.P
The Base Definitions volume of POSIX.1\(hy2017,
.IR "\fB<stdio.h>\fP"
.\"
.SH COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.1-2017, Standard for Information Technology
-- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 by the Institute of
Electrical and Electronics Engineers, Inc and The Open Group.
In the event of any discrepancy between this version and the original IEEE and
The Open Group Standard, the original IEEE and The Open Group Standard
is the referee document. The original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
.PP
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .