a UTF-8 encoded string
the maximum length of str to use, in bytes. If len < 0, then the string is nul-terminated.
location to store number of bytes read, or null. If null, then G_CONVERT_ERROR_PARTIAL_INPUT will be returned in case str contains a trailing partial character. If an error occurs then the index of the invalid input is stored here.
a pointer to a newly allocated UCS-4 string. This value must be freed with glib.global.gfree. If an error occurs, null will be returned and error set.
Convert a string from UTF-8 to a 32-bit fixed width representation as UCS-4. A trailing 0 character will be added to the string after the converted text.