c++ - How to check for cancel button in custom action without doing anything else -

I know that when I use something called log in using :: MsiProcessMessage (hModule, INSTALLMESSAGE (INSTALLMESSAGE_INFO) Put .. ..); that I can check that the return value is IDCANCEL and ERROR_INSTALL_USEREXIT is returned for the Windows Installer.

How can I check that return value or put something in the log without progress bar?

I believe the information message will be placed in the call log you mentioned. But apart from that, you have to put something in the log or change the progress bar? If your action takes a long time, then it should report progress. If this is low and you never call MSI process messages, then Windows Installer will cancel immediately afterwards. The only problem is that if you call the MSI process message and cancel it without reporting it.