FSEEKO(3) Linux Programmer's Manual FSEEKO(3)
fseeko, ftello - seek to or report file position
int fseeko(FILE *stream, off_t offset, int whence);
off_t ftello(FILE *stream);
The fseeko() and ftello() functions are identical to fseek() and
ftell() (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 compi-
#define _FILE_OFFSET_BITS 64
will turn off_t into a 64-bit type.
These functions are found on SysV-like systems. They are not present
in libc4, libc5, glibc 2.0 but available since glibc 2.1.
The fseeko and ftello functions conform to SUSv2.