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);
 
[Note] Note
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
fseeko(), ftello():
_FILE_OFFSET_BITS == 64 || _POSIX_C_SOURCE >= 200112L

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 defining _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 indicate 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 attributes(7).

Interface Attribute Value
fseeko(), ftello() Thread safety MT-Safe

CONFORMING TO

POSIX.1-2001, POSIX.1-2008, SUSv2.

NOTES

The declarations of these functions can also be obtained by defining the obsolete _LARGEFILE_SOURCE feature test macro.

SEE ALSO

fseek(3)

COLOPHON

This page is part of release 5.11 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/.


  Copyright 2001 Andries Brouwer <aebcwi.nl>.

%%%LICENSE_START(VERBATIM)
Permission is granted to make and distribute verbatim copies of this
manual provided the copyright notice and this permission notice are
preserved on all copies.

Permission is granted to copy and distribute modified versions of this
manual under the conditions for verbatim copying, provided that the
entire resulting derived work is distributed under the terms of a
permission notice identical to this one.

Since the Linux kernel and libraries are constantly changing, this
manual page may be incorrect or out-of-date.  The author(s) assume no
responsibility for errors or omissions, or for damages resulting from
the use of the information contained herein.  The author(s) may not
have taken the same level of care in the production of this manual,
which is licensed free of charge, as they might when working
professionally.

Formatted or processed versions of this manual, if unaccompanied by
the source, must acknowledge the copyright and authors of this work.
%%%LICENSE_END