This library provides utilities that are primarily intended for interactive usage in a threaded Prolog environment. It allows for inspecting threads, manage I/O of background threads (depending on the environment) and manipulating the debug status of threads.

 threads

List currently known threads with their status.

 join_threads

Join all terminated threads.

 interactor is det

 interactor(?Title) is det

Run a Prolog toplevel in another thread with a new console window. If Title is given, this will be used as the window title.

 thread_run_interactor

Attach a console and run a Prolog toplevel in the current thread.

 thread_has_console is semidet

True when the calling thread has an attached console.

See also

- attach_console/0

 attach_console is det

 attach_console(?Title) is det

Create a new console and make the standard Prolog streams point to it. If not provided, the title is built using the thread id. Does nothing if the current thread already has a console attached.

 open_console(+Title, -In, -Out, -Err) is det[private]

Open a new console window and unify In, Out and Err with the input, output and error streams for the new console.

 xterm_args(-List) is nondet[multifile]

Multifile and dynamic hook that provides (additional) arguments for the xterm(1) process opened for additional thread consoles. Each solution must bind List to a list of atomic values. All solutions are concatenated using append/2 to form the final argument list.

The defaults set the colors to black-on-light-yellow, enable a scrollbar, set the font using Xft font pattern and prepares the back-arrow key.

 enable_line_editing(+In, +Out, +Err) is det[private]

Enable line editing for the console. This is by built-in for the Windows console. We can also provide it for the X11 xterm(1) based console if we use the BSD libedit based command line editor.

 detach_console(+ThreadId) is det[private]

Destroy the console for ThreadId.

 tspy(:Spec) is det

 tspy(:Spec, +ThreadId) is det

Trap the graphical debugger on reaching Spec in the specified or any thread.

 tdebug is det

 tdebug(+Thread) is det

Enable debug-mode, trapping the graphical debugger on reaching spy-points or errors.

 tnodebug is det

 tnodebug(+Thread) is det

Disable debug-mode in all threads or the specified Thread.

 tbacktrace(+Thread) is det

 tbacktrace(+Thread, +Options) is det

Print a backtrace for Thread to the stream user_error of the calling thread. This is achieved by inserting an interrupt into Thread using call_in_thread/2. Options:

depth(+MaxFrames)

Number of stack frames to show. Default is the current Prolog flag backtrace_depth or 20.

Other options are passed to get_prolog_backtrace/3.

bug

- call_in_thread/2 may not process the event.

 thread_get_prolog_backtrace(+Depth, -Stack, +Options)[private]

As get_prolog_backtrace/3, but starts above the C callback, hiding the overhead inside call_in_thread/2.

 tprofile(+Thread) is det

Profile the operation of Thread until the user hits a key.

 init_pce[private]

Make sure XPCE is running if it is attached, so we can use the graphical display using in_pce_thread/1.