fseeko, ftello - seek to or report file position
#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)
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.
On successful completion,
fseeko() returns 0, while
ftello()
returns the current offset. Otherwise, -1 is returned and
errno is set
to indicate the error.
See the ERRORS in
fseek(3).
These functions are available under glibc since version 2.1.
For an explanation of the terms used in this section, see
attributes(7).
| Interface |
Attribute |
Value |
| fseeko (), ftello () |
Thread safety |
MT-Safe |
POSIX.1-2001, POSIX.1-2008, SUSv2.
fseek(3)