C++ – How to update a C++ dll without needing to relink the exe with the lib file

Using the LIB tool (included with visual studio) you can generate a lib file from a def file. Asuming your dll source does not include a def file, you have to create one first. You can use dumpbin to assist you. For example: dumpbin /exports ws2_32.dll

In the output you see the names of the functions exported. Now create a def file like this:

LIBRARY WS2_32
EXPORTS
    accept      @1
    bind        @2
    closesocket @3
    connect     @4

The @number is the ordinal in the dumpbin output

Use LIB /MACHINE:x86 /def:ws2_32.def to generete the lib file.

Now you can easily modify the def file, and generate a new libfile each time you rename your dll.

you can verify the libfile using dumpbin: dumpbin /exports ws2_32.lib. You should get the same output as the original lib file.

Windows will load at most one version of each DLL name per process. If it loads a DLL listed in HKEY_LOCAL_MACHINE\Software\Microsoft\Windows NT\CurrentVersion\Windows\AppInit_DLLs, it won't load a similarly-named DLL later. But in AppInit_DLLs you can list a DLL with an explicit path, overriding the normal LoadLibrary() order.

Hence, temporarily put your test DLL in AppInit_DLLs and it will override any other DLL with the same name.