XPLMUnregisterKeySniffer
XPLM_API int XPLMUnregisterKeySniffer(
XPLMKeySniffer_f inCallback,
int inBeforeWindows,
void * inRefcon);
This routine unregisters a key sniffer. You must unregister a key sniffer for every time you register one with the exact same signature. Returns 1 if successful.