turns trace on or off or returns the current state
INCLUDE 'prolib.h' trace(on) trace(off) trace(Trace)
trace(Flag) (i) trace(Flag) (o)
integer(Flag) (i) If Flag equals 0 trace is turned off, otherwise turned on
atom(Flag) (i) the trace mode turned on or off set according to Flag
integer(Flag) (o) If trace is enabled '1' is returned, otherwise '0'
This is a standard prolog built-in. Trace always succeeds an switches trace on or off
according to its argument. 'on' of '1' turn trace on, 'off' or '0' turn it off. If Flag is not bound,
it will be bound to an integer reflecting the trace state.
NOTE: The trace mode can also be switched from the outside via the debug windows of the host server. Also any time a trace() is encountered, the trace state is send to the host server which has to acknowledge the transition. Please consult the Host Server Manual for a detailed description.
trace(on), buggy_code, trace(off).
No runtime errors.
prolog-process, client-server, object