WIX C++ Custom Action

Question

I have a basic WIX custom action:

        UINT __stdcall MyCustomAction(MSIHANDLE hInstaller)
        {   
            DWORD dwSize=0;
            MsiGetProperty(hInstaller, TEXT("MyProperty"), TEXT(""), &dwSize);
            return ERROR_SUCCESS;
        }

Added to the installer:

   <CustomAction Id="CustomActionId" FileKey="CustomDll" DllEntry="MyCustomAction"/>
   <InstallExecuteSequence>
       <Custom Action="CustomActionId" Before="InstallFinalize" />
   </InstallExecuteSequence>

The problem is that, no matter what i do, the handle hInstaller is not valid. I've set the action to commit, deferred, changed the place in InstallExecute sequence, hInstaller is always not valid.

Any help would be appreciated. Thanks.

In what way is it not valid? Are you getting an error back from an API call? — Paul Lalonde, Jan 28 '10 at 03:20
If i make any call that uses the handle, the function will return Invalid_Handle error message. — Adrian Fâciu, Jan 28 '10 at 18:08
ignoring the handle, is the function itself being called correctly? — saschabeaumont, Feb 02 '10 at 04:37
I believe the function was called correctly. Anyway to solve the problem, i've rewritten the setup and the custom dll ( there wasn't a lot of code ), and now it's working ok. — Adrian Fâciu, Feb 02 '10 at 09:04

score 8 · Accepted Answer · answered Mar 16 '10 at 14:48

You need to export the called function so MSI can call it using undecorated C style name

Replace your code with this

    extern "C" _declspec(dllexport) UINT __stdcall MyCustomAction(MSIHANDLE hInstall);

    extern "C" UINT __stdcall MyCustomAction(MSIHANDLE hInstall)
    {   
        DWORD dwSize=0;
        MsiGetProperty(hInstaller, TEXT("MyProperty"), TEXT(""), &dwSize);
        return ERROR_SUCCESS;
    }

score 3 · Answer 2 · edited May 23 '17 at 11:54

3

As mentioned here, the only way to overcome the mangling of a __stdcall is to use:

#pragma comment(linker, "/EXPORT:SomeFunction=_SomeFunction@@@23mangledstuff#@@@@")

This creates a second entry in the DLL export table.

edited May 23 '17 at 11:54

Community

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answered Jun 17 '13 at 04:24

Pierre

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Another way to insure the non-mangled function name is included in the DLL exports, is to EXPORT it in a DEF file, and add it to the Linker Properties (Linker -> Input -> Module Definition File). – Pierre Jun 22 '13 at 10:49

WIX C++ Custom Action

2 Answers2