FSEEKO(3) Linux Programmer's Manual FSEEKO(3)
NAME
fseeko, ftello - seek to or report file position
SYNOPSIS
#include <stdio.h>
int fseeko(FILE *stream, off_t offset, int whence);
off_t ftello(FILE *stream);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
fseeko(), ftello():
_FILE_OFFSET_BITS == 64 || _POSIX_C_SOURCE >= 200112L
(defining the obsolete _LARGEFILE_SOURCE macro also works)
DESCRIPTION
The fseeko() and ftello() functions are identical to fseek(3) and
ftell(3) (see fseek(3)), respectively, except that the offset argument
of fseeko() and the return value of ftello() is of type off_t instead
of long.
On some architectures, both off_t and long are 32-bit types, but defin-
ing _FILE_OFFSET_BITS with the value 64 (before including any header
files) will turn off_t into a 64-bit type.
RETURN VALUE
On successful completion, fseeko() returns 0, while ftello() returns
the current offset. Otherwise, -1 is returned and errno is set to in-
dicate the error.
ERRORS
See the ERRORS in fseek(3).
VERSIONS
These functions are available under glibc since version 2.1.
ATTRIBUTES
For an explanation of the terms used in this section, see at-
tributes(7).
+-------------------+---------------+---------+
|Interface | Attribute | Value |
+-------------------+---------------+---------+
|fseeko(), ftello() | Thread safety | MT-Safe |
+-------------------+---------------+---------+
CONFORMING TO
POSIX.1-2001, POSIX.1-2008, SUSv2.
SEE ALSO
fseek(3)
COLOPHON
This page is part of release 5.07 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
2017-09-15 FSEEKO(3)