fseeko, ftello - seek to or report file position
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)):
_FILE_OFFSET_BITS == 64 || _POSIX_C_SOURCE >= 200112L ||
_XOPEN_SOURCE >= 600
(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
On many architectures both off_t and long are 32-bit types, but
#define _FILE_OFFSET_BITS 64
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 found on System V-like systems. They are not
present in libc4, libc5, glibc 2.0 but are available since glibc 2.1.
This page is part of release 3.65 of the Linux man-pages project. A
description of the project, and information about reporting bugs, can
be found at http://www.kernel.org/doc/man-pages/.