Fanning Software Consulting

Odd Cursor Behavior in Mac OS X

QUESTION: I've noticed odd behavior with the CURSOR command with my new Macintosh computer running OS X. Do you know anything about this?

ANSWER: The CURSOR command accepts a third positional parameter, which is the “wait” state. In other words, it indicates when the cursor should return its location values. The wait state can also be selected by setting the appropriate keyword value (e.g., DOWN, UP, NOWAIT, etc.). For example, this command:

   Cursor, x, y, 3

is the same as this command:

   Cursor, x, y, /Down

Apparently, specifying the wait state with a positional parameter other than zero is broken in Mac OS X in versions 6.2 and 6.3 of IDL (the only versions tested). Setting the wait state with a keyword parameter, however, is not broken and would be the preferred work-around. It is this problem that prevents IDL programs such as PROFILES, for example, from working correctly on Macintosh computers running Mac OS X.

Setting up Your OS X Computer for Science

Several people have asked me for additional information about setting up their Macintosh computers for science applications. I can recommend OS X for Astronomers as a site with useful information.

Web Coyote's Guide to IDL Programming