Signature for the seek callback.
The signature and semantics mostly match POSIX fseek() WITH ONE IMPORTANT
EXCEPTION: the offset is a 64-bit type whereas fseek() is generally 'int'
and 32-bits wide.
\param handle The handle to the data source.
\param offset The new position, relative to \a whence
\param whence \c SEEK_SET, \c SEEK_CUR, or \c SEEK_END
\retval int
\c 0 on success, \c -1 on error.
Signature for the seek callback. The signature and semantics mostly match POSIX fseek() WITH ONE IMPORTANT EXCEPTION: the offset is a 64-bit type whereas fseek() is generally 'int' and 32-bits wide.
\param handle The handle to the data source. \param offset The new position, relative to \a whence \param whence \c SEEK_SET, \c SEEK_CUR, or \c SEEK_END \retval int \c 0 on success, \c -1 on error.