— Macro: int SCM_CHARP (SCM x)

Return non-zero iff x is a character value.

— Macro: unsigned int SCM_CHAR (SCM x)

Return the value of x as a C character. If x is not a Scheme character, the result is undefined.

— Macro: SCM SCM_MAKE_CHAR (int c)

Given a C character c, return its representation as a Scheme character value.