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Pack logtalk -- logtalk-3.98.0/library/process/NOTES.md

This file is part of Logtalk https://logtalk.org/ SPDX-FileCopyrightText: 1998-2025 Paulo Moura <pmoura@logtalk.org> SPDX-License-Identifier: Apache-2.0

Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with the License. You may obtain a copy of the License at

http://www.apache.org/licenses/LICENSE-2.0

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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.