Explain the SYS_DLLS keywords.

Actually there are three key names that exist for the app name SYS_DLLS.

They are:

Load

DLL loaded and ordinal 1 entry point called for every msg queue created in the system

DLL loaded and ordinal 1 entry point called for only the first message queue created on a process

DLL loaded and ordinal 1 entry point called for only the shell's message queue (the first PM queue in the system)

You would use one over another depending on the type of initialization that you require. Most DLL's only need to be initialized once for the system and are thus LoadOneTime, some DLLs like PMCTLS have per process initialization and thus are LoadPerProcess, and then there is the very rare case of DLLs that need to perform some function every time a message queue is created and these are specified as Load. Note: that anything other than LoadOneTime is a significant performance hit on the system. Note: also that in addition to your INITIALIZATION/TERMINATION function specified in the DEF file for your DLL (which is a new feature in 2.0), your ORDINAL 1 entry point in your DLL is also called. Be careful with this as I have seen some pretty strange results if you have an ordinal 1 entry point that has nothing to do with initialization. In addition, remember to never ever create a message queue inside of your initialization routine. Always call WinQueryAnchorBlock if you need a HAB for some API.

As for shared resources, if you need resources on multiple processes then they need to be created on multiple processes as they won't be valid on any process other than the one you loaded. I believe that this is the reason PMCTLS is LoadPerProcess. You have a few options here, 1) you can store your resources in shared memory, and 2) for icons you can call WinSetPoinerOwner to make your icons shared across the entire system.