InstallShield 2012 Express Edition User Guide - Knowledge Base ...

Chapter 10: Customizing Installation Behavior
Using Custom Actions
Table 10-1: Types of Custom Actions (cont.)
Type of Action Description
Standard DLL This type of action is an InstallShield extension that lets you call functions from
C-callable DLLs. The type of function prototype that you select for the action
(classic or new) determines which signature you must use for your function.
• Classic—The prototype in this type of DLL must follow the same format
that was used in early versions of InstallShield Express.
• New—The prototype in this type of DLL uses the same signature that is
required for MSI DLL custom actions. If you want to use this type of
signature for a new custom action that you are adding to your project, it is
recommended that you use an MSI DLL custom action instead of a
standard DLL, since an MSI DLL action offers more flexible scheduling
options.
Important: Note that for standard DLL custom actions, a non-zero return value
indicates success, and a return value of zero indicates failure. For MSI DLL
custom actions, a return value of zero indicates success; non-zero return
values indicate statuses such as failure or cancellation.
Executable File This type of action launches an executable file that is included in your
installation (as a temporary support file or installed with the product) or that
already exists on the target system.
A benefit of this action type is that a lot of operating system functionality is
exposed in executable files. For example, this type of action lets your
installation open text files and other common file types, set permissions on
existing directories, and launch batch files.
Executable-file actions do not have access to the running installation session.
Thus, you cannot pass Windows Installer properties in to the executable file
(except as command-line arguments) or back from the executable file (except
through external storage, such as the registry or a file).
Note that to open a document or launch a batch file, you must explicitly refer to
an executable file that handles that type of document.
VBScript or JScript This type of action runs VBScript or JScript code.
Benefits of this action type include:
• Script actions are often easy to implement.
• Unlike executable-file actions, this type of action can use the Windows
Installer API to access the running Windows Installer session and work with
properties, directories, and so on.
• This type of action can be useful for simple tasks such as string
manipulation.
Note that VBScript and JScript actions often trigger antivirus or antispyware
programs when they access or modify the target system.
222 ISE-1800-UG01 InstallShield 2012 Express Edition User Guide