Windows dll delay loading

Here is a screenshot of depends. DLL and R. DLL are both highlighted as missing — this is extremely useful for figuring out dependent DLL load issues.

The SysInternals Process Monitor is an incredibly useful low-level Swiss Army Knife utility that can be used, among other things, to monitor dynamic library loading activity as it occurs, using the file activity view. The subsequent dependent DLL loading activity is highlighted.

The term delay-loading typically is used to apply to delaying the load of a module until a function in that module is called. But import resolution happens at load time, not run time. Commenter bruteforce tried to create a forwarder to a nonexistent function, and then tried to link to the forwarder DLL. As we saw above, this triggers an attempt to resolve the forward by loading the forwarded-to DLL and looking for the function.

If this fails, then the original import request is declared to have failed. This all happens as part of the import resolution process. And as we saw many years ago, Win32 fails a module load if an import cannot be resolved. Since the forwarder cannot be resolved, the load fails. Import forwarding functionality is completely unsuitable for functions whose presence you wish to detect and respond to at runtime. As with all imports, an import failure is considered a fatal error.

If you want delay-loading, then you need to do delay-loading. Forwarding is not delay-loading. Comments are closed. I wrote a book Ground rules Disclaimers and such My necktie's Twitter. DLL forwarding is not the same as delay-loading Raymond.

February 4th, To compare strings independent of case, just convert both to either all upper case or all lower case. As for the difference between throwing an exception and returning an error code, there might be a Windows programming solution but that is outside the scope of this forum. I think there is a Windows function that can be called to set Windows to return an error code.

The problem is that the second string comes from the delay load descriptor in the EXE image and is placed there by the linker. I don't control that second string, and the code that compares them. I don't know how the linker determines what case to use for the DLL name - that is my question. My concern is that according to the samples an error code should be returned. I see that others have had this problem as well searching from google. The case sensitivity is a clear bug, IMO.

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