1.0 idea - ntdll - add a messagebox for missing dlls

Paul Chitescu paulc at voip.null.ro
Tue Apr 29 09:44:53 CDT 2008

On Tue, 29 Apr 2008, Peter Beutner wrote:
> Steven Edwards schrieb:
>> On Mon, Apr 28, 2008 at 3:51 AM, Steven Edwards <winehacker at gmail.com> wrote:
>>> On Sun, Apr 27, 2008 at 9:19 AM, Dan Kegel <dank at kegel.com> wrote:
>>> >  2. You never clear that environment variable... what happens
>>> >  when an app just tests for the existence of a DLL by
>>> >  trying to load it?  We don't want to print an error then.
>>> >  (That's why I originally suggested clearing the env var
>>> >  after the app finished loading.  That's still broken -- it
>>> >  won't catch errors in helper exes -- but it's better than nothing.)
>>>  I assume you mean if the application is just checking manually for the
>>>  dll via GetModuleHandle or LoadLibrary? I'll write a test case for
>>>  this to see if it causes a problem. My assumption was that the failure
>>>  case for that was at a higher level but I'll check with a test case. I
>>>  don't think we need to clear the variable....what I mean is I wonder
>>>  if there is a way to set the variable to be inherited by all child
>>>  processes launched by start.exe.so in unix mode. I'll look in to this
>>>  as well.
>> I assumed the code path must be different so I wrote a test app that
>> tried to do a GetProcAddress or LoadLibrary on a non-existent dll and
>> was right, It did not throw the messagebox.
> But I think it will still trigger the msg box if the application is checking for
> an existent foo.dll via LoadLibrary and foo.dll depends on a missing xyz.dll.
> It won't trigger if you clear the environment variable as Dan said.
> I'm not sure though which way is the right one here.

Windows doesn't do that - when my application tries to load a module that 
links against a missing DLL then LoadLibrary simply fails without showing 
any message. The "ignore it if LoadLibrary fails" logic is common in many 
programs that use optional plugins.

Paul Chitescu

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