Allows the extension DLL to verify its system requirements. This is in addition to and after the standard system checks have been performed as specified on the Requirements project page.

If one or more requirements are not met, the extension DLL should alert the user before returning, unless performing a silent install. Calling TixMessageBox is the recommended method, because it will not display the message box in quiet mode.

Action scheduling

This message is sent by the CheckRequirements standard action; its scheduling depends on the action sequences used by the installer, but it is typically called during both the MainInstall action sequence and by the WelcomeDlg dialog box during the initial UIFirstInstall action sequence.


Not used

Result code

If this message is handled, pMessage->lResult must be set to one of the following result codes: