GLib.filename_from_utf8

function filename_from_utf8(utf8string: String, len: Number(gssize)): [return_value: ByteArray, bytes_read: Number(gsize), bytes_written: Number(gsize)] {
    // Gjs wrapper for g_filename_from_utf8()
}

Converts a string from UTF-8 to the encoding GLib uses for filenames. Note that on Windows GLib uses UTF-8 for filenames; on other platforms, this function indirectly depends on the [current locale][setlocale].

utf8string: a UTF-8 encoded string.
len: the length of the string, or -1 if the string is nul-terminated.
return_value: The converted string, or null on an error.
bytes_read: location to store the number of bytes in the input string that were successfully converted, or null. Even if the conversion was successful, this may be less than len if there were partial characters at the end of the input. If the error #G_CONVERT_ERROR_ILLEGAL_SEQUENCE occurs, the value stored will the byte offset after the last valid input sequence.
bytes_written: the number of bytes stored in the output buffer (not including the terminating nul).