ftell (3p) - Linux Manuals

ftell: return a file offset in a stream

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.

NAME

ftell, ftello - return a file offset in a stream

SYNOPSIS

#include <stdio.h>

long ftell(FILE *stream);

off_t ftello(FILE *stream);

DESCRIPTION

The ftell() function shall obtain the current value of the file-position indicator for the stream pointed to by stream.

The ftello() function shall be equivalent to ftell(), except that the return value is of type off_t.

RETURN VALUE

Upon successful completion, ftell() and ftello()  shall return the current value of the file-position indicator for the stream measured in bytes from the beginning of the file.

Otherwise, ftell() and ftello() shall return -1, cast to long and off_t respectively, and set errno to indicate the error.

ERRORS

The ftell() and ftello() functions shall fail if:

EBADF

The file descriptor underlying stream is not an open file descriptor.

EOVERFLOW

For ftell(), the current file offset cannot be represented correctly in an object of type long.

EOVERFLOW

For ftello(), the current file offset cannot be represented correctly in an object of type off_t.

ESPIPE

The file descriptor underlying stream is associated with a pipe or FIFO.

The ftell() function may fail if:

ESPIPE

The file descriptor underlying stream is associated with a socket.

The following sections are informative.

EXAMPLES

None.

APPLICATION USAGE

None.

RATIONALE

None.

FUTURE DIRECTIONS

None.

COPYRIGHT

Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 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 .