RXSem, at the basest level, is a DLL that provides your REXX scripts with access to the OS/2 semaphore APIs. Look at this library from a higher perspective, however, and you can see an OS/2 semaphore management subsystem. Over and above the simple API calls that OS/2 allows (all of which are available through RXSem), RXSem will keep track of your semaphores for you, allowing you to query RXSem for which semaphores you have in use for your given process.

RXSem is also developer-friendly with a unique capability for returning error messages that describe the current problem instead of aborting your script, as is normal for REXX libraries.

Finally, a few other goodies are thrown in which can greatly simplify your REXX code in a number of other areas (priority settings, process detection and killing, launching Netscape via DDE, word wrap, set window title).