Working with ENVI Zoom 4.4 and IDL "SEM_CREATE" routine on Mac OS X 10.5 (Leopard)
Topic:
On Mac OS X 10.5 (Leopard) systems, ENVI Zoom 4.4 will not function properly. Additionally, the IDL routine,
SEM_CREATE, will not create a semaphore reference. These two issues are related in that the affected ENVI Zoom functionality relies on the IDL
SEM_CREATE routine.
This article discusses the errors that might be encountered and an approach that will allow users to work around this problem for ENVI Zoom 4.4 and IDL 6.4.1*.
*Note that IDL 6.4 will not work properly on Mac OS X 10.5. It is recommended that the IDL 6.4.1 patch be applied if using IDL on Mac OS X 10.5. The IDL 6.4.1 patch for Mac OS X 10.5 can be obtained from the following tech tip article: Tech Tip #4284 -- "IDL 6.4.1 update for Mac OS X 10.5" |
Discussion:
SYMPTOMS:ENVI ZoomFor ENVI Zoom 4.4, operations such as File->Save As... or accessing the Feature Extraction (FX) or RX Anomaly Detection functionality will fail and even crash ENVI Zoom. Error messages encountered may be similar to the following:
- Error
Failed to create semaphore.
- Warning
The following error was encountered: SEM_LOCK: Unknown semaphore name provided: MEMSEG_1954281556_SEM. Please consult the supplier of the application.
SEM_CREATE()
The IDL SEM_CREATE() function will unexpectedly return a 0 (error) instead of 1 (success).
WORKAROUND:A workaround for these issues follows:
- Launch IDL 6.4.1 (or ENVI+IDL 4.4) (even in 7-minute demo mode)
- Issue the following command at the IDL (or ENV+IDL) command prompt:
PREF_SET, 'IDL_TMPDIR', '/tmp/', /COMMIT
- Exit IDL (or ENVI+IDL)
Subsequent sessions ENVI Zoom or use of the IDL SEM_CREATE routine should then work as expected.
Note that this workaround should be employed by each user of ENVI Zoom or IDL that encounters these issues on Mac OS X 10.5.
<< Keywords: rxd, envi fx, semaphores >>
Solution:
[Edit this field in the IDL-based Tech Tip Editor, v62]