register_ftrace

Feedback.register_ftrace :
  (string * ((unit -> int) * (int -> unit)) * int) -> unit

Registers a trace that is accessed by a set/get pair of functions.

A call to register_ftrace(nm, (g,s), m) registers an integer-valued trace variable that is updated with the s function and whose value is read with the g function. The variable is given the name nm and the variable’s maximum allowed value is m. The trace’s default is the value of g(), which is called just once as part of the registration procedure.

Failure

Fails if the given name is already in use as a trace variable, or if the maximum or the default value (returned by g()) is less than zero.

Comments

The two functions provide a more general way of accessing something that may not be actually be an integer reference, even though this is the interface that the various trace functions present.

See also

Feedback, Feedback.current_trace, Feedback.register_trace, Feedback.register_btrace, Feedback.set_trace, Feedback.trace, Feedback.traces