Function svn_io_read_version_file 

pub unsafe extern "C" fn svn_io_read_version_file(
    version: *mut c_int,
    path: *const c_char,
    pool: *mut apr_pool_t,
) -> *mut svn_error_t

Set @a *version to the integer that starts the file at @a path. If the file does not begin with a series of digits followed by a newline, return the error #SVN_ERR_BAD_VERSION_FILE_FORMAT. Use @a pool for all allocations.