The Investor/RT Software Developer's Kit (SDK) is a toolkit for developing plug-in technical indicators and trading signals for use in Investor/RT. Plug-ins are written in either the C or C++ programming language. On the Windows platform, plug-ins are implemented as "Dynamic Link Libraries" (DLL's). On the Macintosh platform, plug-ins are developed as "Shared Libraries" (slb files). The SDK includes a manual and sample code for a plug-in that calculates two moving average lines and generates signals where the two moving average lines intersect.

The SDK is available at no additional charge to all licensed users of Investor/RT. Linn Software will provide developer support by email and telephone consultation on a fee basis to SDK users. To order the SDK please complete the SDK Non-Disclosure Agreement, electronically sign and email to info@linnsoft.com.  The SDK will then be sent to you via email.

• Join The Investor/RT Developer's Forum (Yahoo! Group)
• More About Plug-In Indicators
• Using Plug-In Indicators
• Adding A Plug-In Indicator To A Chart
• Using Plug-In Indicators In Scans, Signals, and Custom Indicators

More About Plug-In Indicators

An Investor/RT "plug-in" is a computer program for calculating a technical indicator or trading signal. Plug-ins are not built into Investor/RT directly. Plug-ins can be developed externally by Investor/RT users having the requisite computer programming skills or by third party software vendors wishing to market proprietary technical indicators and/or trading signals to Investor/RT users.

Typically, plug-ins are written in either the C or C++ programming language. On the Windows platform, plug-ins are implemented as "Dynamic Link Libraries" (DLL's). On the Macintosh platform, plug-ins are developed as "Shared Libraries" (shlb files). These DLL or shlb files are placed into the "plugins" directory/folder located inside the Investor/RT startup folder. At startup, Investor/RT inspects the plugins directory/folder and creates a list of the DLL's or shlb files located there. Just like any of the built-in indicators, each plug-in becomes available for use in Investor/RT.

Programmers interested in developing plug-in indicators for use in Investor/RT may acquire the "Investor/RT Software Developer's Kit (SDK)". The Investor/RT SDK contains complete instructions for developing I/RT plug-ins, along with sample code for both Windows and Macintosh platforms. Interested parties must execute a non-disclosure agreement (NDA). The SDK is available at no additional charge to all licensed users of Investor/RT. Linn Software will provide developer support by email and telephone consultation on a fee basis to SDK users.

Using Plug-In Indicators

To demonstrate how these indicators are implemented, we will use Investor/RT’s sample plug-in called "IRTSAMPLE". 

Windows users: In the "plugins" directory, locate the file called IRTSAMPLE.DLL. This file contains the programming for this simple indicator (IRTSAMPLE computes two simple moving averages of user-specified periods and produces a signal for each bar where the two moving averages crossover on another.). 

Macintosh users: In the “plugins” folder, locate the file called IRTSAMPLE. Get Info will show the file's type to be "Shared Library".

Go to Setup: Preferences: Charts: Technical Indicators. From the list of indicators, select "Plug-in Indicator” and view the settings. A list of available plug-ins is shown at the top. Select "IRTSAMPLE" from the list and the description of the plug-in will appear in the scrollable text box. This text is supplied to Investor/RT by the plug-in itself. It is used to convey a description of what the plug-in does and how to enter any required user parameters. The Parameters entry box accepts up to 80 characters of arbitrary text that is made available to the plug-in for the purpose of setting preferences for the indicator.

In this simple example, IRTSAMPLE expects the user to enter two numbers into the parameter box indicating the desired periods of the simple moving averages.

A plug-in indicator can be drawn as a continuous line, a connected line or as a solid/hollow histogram. Signals computed by a plug-in appear on the chart as “markers” showing each bar where the signal is true. A color control allows specification of the line or histogram color properties. If the plug-in requests it, two optional reference line checkboxes are provided, similar to the setup for Investor/RT custom indicators. In this example the plug-in does not require reference lines.

Adding a Plug-In Indicator to a Chart

To add a plug-in indicator to the current chart window, click the "Add Technical Indicator" button on the chart's toolbar and select "Plug-in Indicator". Choose IRTSAMPLE from the list and enter the desired period into the parameter box. By default, all plug-in indicators are graphed in a new pane. To overlay the indicator on the instrument data, select the pane before adding the indicator, or simply drag and drop the indicator later. Press OK and the plug-in will be added to the chart. The Plug-in settings are edited in the same way as any indicator. To access the settings, right-click (or command click) on the line, change the parameters and click OK.

Using Plug-in Indicators in Scans, Signals, or Custom Indicators

Any plug-in indicator can be used as a token in the RTL language. In the setup window for scans, signals or custom indicators, select "PLUGIN" from the list of available tokens. The setup for the Plug-in Indicator will appear. Choose the IRTSAMPLE plug-in, set the period parameters and press OK. In the list of token on the right, a token called PLUGIN will appear. You can rename the token, e.g., call it SMA for "simple moving average". When using several plug-in indicators within the same scan, signal or custom indicator, you must give each one a unique token name to be able to reference each plug-in in your formula. When a plug-in calculates more than one array results as in this example, the scan setup window for the plug-in has a menu button with which to specify which of the array results to reference. If you wish to reference just the signal array for example, you would specify array3 since array1 and array2 represent the two simple moving average. If you have a plug-in that calculates multiple arrays and you wish to reference more than one of the resulting arrays, you will have to add the PLUGIN indicator two (or more) times to the scan, specifying a different array for each instance and specifying a unique name for each plug-in token to you can reference them unambiguously in the scan formula.

Plug-in indicators have exactly the same functionality as built-in indicators. The only difference is that the computation is programmed externally and "linked" into the Investor/RT system using the plug-in mechanism.

Using Plug-ins in Custom Columns   Plug-in indicators can be used as the source for custom columns in quote pages. By setting up the custom column as the technical indicator "Plug-in Indicator", the indicator can be referenced directly. You can also create custom columns that reference the results of scans and/or custom indicators using the plug-in's capabilities.