.. _library_process:

process

This library provides a portable abstraction over process handling predicates found in some backend Prolog systems. Currently supports ECLiPSe, GNU Prolog, SICStus Prolog, SWI-Prolog, Trealla Prolog, and XVM.

API documentation

Open the `../../docs/library_index.html#process <../../docs/library_index.html#process>`__ link in a web browser.

Loading

To load all entities in this library, load the loader.lgt file:

::

| ?- logtalk_load(process(loader)).

Testing

To test this library predicates, load the tester.lgt file:

::

| ?- logtalk_load(process(tester)).

Usage

The process object provides the following predicates for portable process handling:

• create(Executable, Arguments, Options) - Creates a new process
• wait(Process, Status) - Waits for a process to terminate
• kill(Process, Signal) - Terminates a process with a specific signal
• kill(Process) - Terminates a process using the default signal (SIGKILL)

  The create/3 predicate supports the following options:

• process(Pid) - Unifies Pid with the process identifier (an opaque ground term)
• stdin(Stream) - Binds Stream to the process standard input
• stdout(Stream) - Binds Stream to the process standard output
• stderr(Stream) - Binds Stream to the process standard error Note: Process identifiers (PIDs) should be treated as opaque ground terms. Their internal representation varies between backend Prolog systems.

  Example:

  ::

  | ?- process::create('/bin/echo', ['hello.'], [stdout(Out), process(PID)]), read_term(Out, Term, []), close(Out). Out = ..., PID = ..., Term = hello.