# `help`

This tool provides basic on-line help for Logtalk when running in a limited set of operating-systems.

## API documentation

This tool API documentation is available at:

../../docs/library_index.html#help

For sample queries, please see the `SCRIPT.txt` file in the tool directory.

## Loading

    | ?- logtalk_load(help(loader)).

## Testing

To test this tool, load the `tester.lgt` file:

    | ?- logtalk_load(help(tester)).

## Supported operating-systems

Currently, support is limited to Linux, macOS, and Windows.

On Windows, the `start` command must be available. On Linux, the `xdg-open` command must be available. On macOS, the command `open` is used.

This tool relies on the library portable operating-system access abstraction.

## Known issues

On macOS, the `open` command used to open documentation URLs drops the anchors, thus preventing navigating to the specified position on the documentation page.

ECLiPSe defines a `help` prefix operator that forces wrapping this atom between parenthesis when sending messages to the tool. E.g. use `(help)::help` instead of `help::help`.