XPLM_API const char * XPLMGetVirtualKeyDescription(
                         char                 inVirtualKey);    

Given a virtual key code (as defined in XPLMDefs.h) this routine returns a human-readable string describing the character. This routine is provided for showing users what keyboard mappings they have set up. The string may read ‘unknown’ or be a blank or NULL string if the virtual key is unknown.