fseeko, ftello - seek to or report file position
Standard C library (
libc,
-lc)
#include <stdio.h>
int fseeko(FILE *stream, off_t offset, int whence);
off_t ftello(FILE *stream);
fseeko(),
ftello():
_FILE_OFFSET_BITS == 64 || _POSIX_C_SOURCE >= 200112L
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 since glibc 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.
The declarations of these functions can also be obtained by defining the
obsolete
_LARGEFILE_SOURCE feature test macro.
fseek(3)