Function
GLibascii_xdigit_value
Description
Determines the numeric value of a character as a hexadecimal digit. If the
character is not a hex digit according to g_ascii_isxdigit(),
-1 is returned.
Differs from g_unichar_xdigit_value() because it takes a char, so
there’s no worry about sign extension if characters are signed.
Differs from g_unichar_xdigit_value() because it takes a char, so
there’s no worry about sign extension if characters are signed.