The Mac OS Gestalt Manager tools
made by Jean-Pierre CURCIO


What is Gestalt ?

Gestalt is a function for programers that was born with the Macintosh Operating System in version 6.0.4. It provides a method to get information about the current system’s environment: provide it a selector and Gestalt returns a 32-bit value, which needs to be interpreted. If unable to obtain the requested information, Gestalt instead returns an error code (a non-zero number).

To help with this interpretation, Jean-Pierre Curcio wrote two applications: Gestalt.Appl and GestLab.

GestLab is recommanded for systems with Mac OS version 8.1 and higher, while Gestalt.Appl is provided for users running earlier system versions. GestLab 1.2.2 is the last version running on 68K machines.

Use of these applications is free.

Help to improve and extend GestLab’s extensive database by sending the author your comments as well as any configuration file that contains new information which is not included in the lastest published version:

Final US versions
available for download
(use Aladdin’s StuffIt Expander to decompress)

(binhexed - 307 KB)

GestLab 1.3.1 (29 Sep 2002)

(binhexed - 109 KB)

GestLab Database #22 (2 Jan 2004) 

(binhexed - 450 KB)

GestLab 1.2.2 (17 Feb 2001)

(binhexed - 160 KB)

Gestalt.Appl 2.7.10 (25 Oct 1998)

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Gestalt.Appl was born in 1991. The last version of Gestalt.Appl (25 October 1998) was numbered 2.7.10 and works on virtually any machine starting with the Macintosh Plus running any System version. It has been replaced by GestLab.

Main feature: displays information about 225 selectors that are present in the included database. This information is dynamic, and depends on the actual system environment.

Local configuration information can be saved or exported, and opened later.

Thanks to the ‘tabl’ selector, you can display a list of all Gestalt selectors posted by the System and Extensions.

Gestalt.Appl will no longer be updated. Users with the most recent Mac OS versions and the lastest machines are advised to use GestLab instead.


CAUTION!: starting with version 1.1, the application and database are separate files. In order to use it, you must download both files (GestLab and GestLab Database), and place them in the same folder.
GestLab 1.2.2 should work on any Macintosh running Appearance Manager.
GestLabXCapt is included and needs Mac OS X.

To properly manage the user interface, GestLab requires the Appearance Manager, provided by Apple with Mac OS versions starting with 8.1. To use GestLab on earlier systems you need to install the Appearance Manager which is freely available for dowload from Apple’s website.

GestLab has many more features than Gestalt.Appl. These include:
• a more elaborate interface;
• a more sophisticated interpretation of selectors;
• a richer database;
• search functions for the database;
• automatic detection of new Gestalt selectors;
• best-guess for the origin of unknown selectors;
• comparison of two configurations;
• and more...

GestLab Database will continue to be updated as long as users like you notify me about new selectors.

Question: why is GestLab not yet carbonized?
Answer (from Apple): the Gestalt Manager on Mac OS X does not currently provide any means to get the entire list of selectors.
But you can use the GestLabXCapt application provided with GestLab 1.3 to capture a predefined list of selectors under Mac OS X. You can then examine it under Classic.

René G. A. Ros had a Web site devoted to Gestalt (but no longer maintained):