Help Server
The IDL help system uses infrastructure provided by the Eclipse framework to find and display help content. As part of this infrastructure, the Eclipse framework installs a Java servlet engine — a web server that has features that allow it to execute Java code — and uses it to serve up help content.
When the IDL help system starts, this help server is automatically started in a separate process. It waits for requests from the Help view or Help browser (either the internal browser or an external web browser) and provides content when asked. In addition, when the IDL Workbench is running, the help server provides communication between the help interface and the Workbench itself, allowing IDL code displayed in the help system to be executed directly in IDL by clicking on a hyperlink.
If you use the IDL Workbench, the help server is started automatically when the help system is launched, and shut down automatically when the Workbench is closed. On Windows and Linux systems, which support the standalone help viewer, the help server starts automatically and shuts down automatically when using IDL in command line mode and when you launch the IDL help separately (via an IDL Help icon or the idlhelp command) as well. On Macintosh and Solaris (Sparc) systems, the help server is started automatically, but it is not shut down automatically when the help viewer is closed. You can shut the help server down manually as described in Controlling the Help Server.
Improving Help System Performance
If the help system is slow to start on your system, you may want to start the IDL help server when your system starts up and simply leave it running. If the help system is already running when IDL starts, requests for the help system will use the running server. To start the help server automatically, place the idlhelp command in the appropriate location for your system (in the Startup folder on Windows systems, for example, or in one of the /etc/rc files on a UNIX system). To ensure that the server stays running if the standalone help viewer is closed, specify the -noautoshutdown argument to the idlhelp command.
Controlling the Help Server
The idlhelp program controls the IDL help server. On Macintosh, Linux, and Solaris (Sparc) systems, idlhelp is located in the bin subdirectory of the IDL installation directory. On Windows systems, idlhelp is located in the idlde directory of the IDL installation directory.
The following sections describe the behavior of the help server when it is started manually, using the idlhelp command. When the help server is started by the IDL Workbench, it always starts automatically when you request help and shuts down automatically when you close the Workbench.
Starting the Help Server
To start the help server manually, change to the directory where the program file is located and give the following command
To start the help server so that it will answer requests to a specific address and port, use a command like
where the server_host value is the IP address of the computer on which the server is running; 127.0.0.1 represents the local machine. The server_port may be any valid port number. Note the presence of the -vmargs flag before the -Dserver_host and -Dserver_port values.
Keeping the Help Server Running
By default, the help server will shut down automatically when the internal help browser closes. You can choose to leave the help server running after the internal help browser has closed by starting the server explicitly with the -noautoshutdown flag:
idlhelp -noautoshutdownNote
This flag can be combined with theserver_hostandserver_portvalues shown in the previous section.
If you use an external web browser to connect to the help server — either because the internal help browser is not supported or because you prefer the web browser interface — the help server will not shut down automatically.
Stopping the Help Server
To stop the help server manually, change to the directory where the program file is located and give the following command
Displaying Topics in the Help Browser
If the help server is already running, you can display a topic with the following command:
where <TOPIC> is a string containing the base name of the HTML file to be displayed (do not include the .html extension).
Controlling Where Help System Configuration is Stored
By default, configuration information for the stand-alone help system is stored in the .idl subdirectory of the user's home directory. To store configuration information in another location, provide the
flag to the idhelp command, where <LOCATION> is the path to the directory where information should be stored.
