|What are the "Windows Installer" and "Platform" SDKs?|
The Windows Installer or msi Software Development Kit is one subcomponent of a much larger Windows Platform SDK (although it is also often available separately!). For most purposes it is enough to download and install the Windows Installer SDK (for example to install "ORCA").
The the Windows Installer SDK is no longer fully self contained (for example it refers to the platform sdk file "specstrings.h") so unless you have the full platform SDK installed problems may occur if you try to build DLLs (for example with the "DllCa-C" command) as Microsoft now appear to assume that you will install the whole platform sdk (consistency wouldn't hurt, tell Microsoft if you can be bothered).
MAKEMSI will attempt to locate the install directory of the SDK and configure the "PLATFORM_SDK_DIR" & "INSTALLER_SDK_DIR" definitions.
|Where can I find them?|
Getting the SDKs:
|Why do I want them?|
The Windows Installer SDK contains miscellaneous MSI database tools, example custom actions written in C and VBScript, C header files and libraries, "blank" MSI and MSM databases, and more. As mentioned above the "DllCa-C" command requires the complete platform sdk to supply all the include files and libraries you will require.
Specifically I tend to use:
If you need to manipulate Windows Installer databases then the "samples" directory is worth a good look.