What is DLLWrap.dll used for in InstallShield?

Question

I am working on an older InstallShield 2010 installer. It puts down DLLWRAP referenced from programfiles\installshield. There are two Custom actions that call functions DLLWrapCleanup after install finialize and DLLWrapStartup after SetupCompleteSuccess.

Can anyone explain what this is and what it does - or even if it is needed? Thanks.

Answer 1

As Installsheild Help describes here: it is a helper DLL for custom actions from a standard DLL.

If you change your custom actions from "standard" to "msi dll" you can remove the DLL and the dllwrap actions from your ISM.

Stefan Krueger describes the differences here.

A "MSI DLL" is a DLL that exports a function that matches the prototype defined in the MSI documentation. This is the only type of DLL that Windows Istaller can use directly as a custom action.

A "Standard DLL" can have (virtually) any prototype. InstallShield adds a wrapper around it that shaows Windows Installer only the MSI DLL interface and translates all additional parameters into properties. So essentially your cuatom action calls a DLL (provided by InstallShield) which calls another DLL (your Standard DLL).

Personally when I started doing this years ago, I used standard DLLs. When I learned the difference I switched to using MSI DLLs.