There are a number of differences between code executing in the application execution context and code in other contexts. The differences are described below:
- It is not part of the command processor state of any specific document.
- It can activate different documents without immediately suspending itself, although it must complete and return before the new active document can process its input.
- AutoLISP is also disabled when prompting for user input in this context.
- In the cases of modeless dialogs and external process-generated ActiveX requests, the code must lock the documents, including the current document. The use of the IAcadDocument methods StartUndoMarker() and EndUndoMarker() will apply a kWriteLock to the document.
- The command facility may not be used from the application execution context, specifically the acedCommandS()/acedCommandC() and acedCmdS()/acedCmdC() functions.
- The AcApDocManager::sendStringToExecute() and AcApDocManager::activateDocument() methods change the active document but do not suspend execution of the code running under the application context. They will suspend execution of code running in a document execution context. The AcApDocManager::sendStringToExecute() method will always queue the string when invoked from the application context, while invoking it from a document context will either queue the string if the activate parameter is kFalse, or immediately suspend the document context if the activate parameter is kTrue.