[gambit-list] integer->char for an integer from interval [128, 255]

Hello! I am working with Gambit interpreter, and the following result is unexpected for me: (string (integer->char 127)) ==> "\177" (string (integer->char 128)) ==> "" (string (integer->char 256)) ==> "\x100" I don't understand why the empty string is returned for an integer from the interval [128, 255]. Could you please exlpain this to me? What should I do to obtain the character that corresponds to an integer from the interval [128, 255]? Dmitry P.S. I am using Gambit version 4.0 beta 12.