Statically linked application - invalid or corrupt dll

Question

I have an application that uses the winInet classes - #include <afxinet.h> and the wininet.dll

I would like to statically link the WinInet function calls in my application as well as the dll, so I followed these steps. I then copied the wininet.dll into my project directory, as I read here.

Upon building I get the following error - wininet.dll : fatal error LNK1136: invalid or corrupt file

My first question is:
-Am I correctly doing what I think is statically linking function calls and the dll?
-If so, why is the dll corrupt with this setup, but works without these changes?

Any help is appreciated. Thank You.

Answer 1

You shouldn't link directly against the DLL. Instead, link against the corresponding import library (should be Wininet.lib). The DLL still needs to be accessible to your application at runtime, of course. The .lib file is needed by the linker to setup proper linkage to the DLL.

Am I correctly doing what I think is statically linking function calls and the dll?

What you're doing is usually called dynamic linkage (more or less dynamic ..), but its (afaik) the only way to go for Windows System APIs. 'Static' linkage would embed the Wininet code directly into your executable, with no need for an external DLL.

Answer 2

"Static Linking" is the process of including the code in your application. By nature, a DLL is a dynamic link library and therefore no, including the DLL in the directory of your application is not static linking - it remains dynamic. The reason for placing it in the directory of the application is so that the application can find it without the need for install.

I don't suppose it is the DLL that is "corrupt" - I suspect you are attempting to static link the DLL into the application which cannot happen. You need instead to include the correct .lib file, whatever that is, in the additional libraries to link with and ensure that the lib file you link with is not the DLL exports package for wininet.dll

Answer 3

When you link with a DLL, there is a corresponding LIB file to use to set up the correct linkage to the functions. For an example, if you are using a USER32.DLL and KERNEL32.DLL, it's corresponding LIBs that needs to be linked would be USER32.LIB and KERNEL32.LIB.

Sometimes it is not so obvious, you can double check by looking at the MSDN for the function in question, when you scroll down towards the bottom of that page it will tell you what library to link with, for an example, look at the Win32API's CreateProcess, as you look at the bottom of the page, it tells you what is the library to use, in this case it's KERNEL32.LIB.

You just referenced a DLL during the linker phase which the linker could not understand the DLL as it is already a compiled library and hence the linker complained that it was "corrupt".

Change that to WinInet.LIB and all should be ok.

Hope this helps, Best regards, Tom.