Convert a sequence of bytes encoded as UTF-8 to a Unicode character. This function checks for incomplete characters, for invalid characters such as characters that are out of the range of Unicode, and for overlong encodings of valid characters.
g_utf8_get_char_validated() returns (gunichar)-2 if
max_len is positive and any of the bytes in the first UTF-8 character
sequence are nul.
A pointer to Unicode character encoded as UTF-8
The data is owned by the caller of the function. The value is a NUL terminated UTF-8 string.
The maximum number of bytes to read, or -1 if