Hook the printf outputs

Question

Markus Forrer 21

I want to get the printf outputs of a foreign C++ dll in my C# application. Is there a way to install a hook?

The foreign c++ dll is encapsulated via my own C++ dll (interface C++ -> C#). I tried to overwrite printf there - unfortunately without success.

Thank you for any hints.

David Lowndes 4,726 Reputation points

2021-04-17T09:31:00.347+00:00

See if the code shown in this thread works for you.
Markus Forrer 21 Reputation points

2021-04-19T04:57:03.757+00:00

Thank you for your answer. Unfortunately I can't get it to work with this example.
Viorel 122.5K Reputation points

2021-04-19T08:24:05.01+00:00

I think that if &printf address is also accessed by DLL (i.e. DLLs are not statically linked), then you can intercept the calls relatively simply using the Detours: https://github.com/microsoft/Detours/wiki.
David Lowndes 4,726 Reputation points

2021-04-19T08:38:31.917+00:00

I'm not too surprised, I think that would only work if both the EXE & DLL are compiled with the same (DLL option) run-time library.

Your answer

David Lowndes 4,726 Reputation points

2021-04-17T09:31:00.347+00:00

See if the code shown in this thread works for you.
Markus Forrer 21 Reputation points

2021-04-19T04:57:03.757+00:00

Thank you for your answer. Unfortunately I can't get it to work with this example.
Viorel 122.5K Reputation points

2021-04-19T08:24:05.01+00:00

I think that if &printf address is also accessed by DLL (i.e. DLLs are not statically linked), then you can intercept the calls relatively simply using the Detours: https://github.com/microsoft/Detours/wiki.
David Lowndes 4,726 Reputation points

2021-04-19T08:38:31.917+00:00

I'm not too surprised, I think that would only work if both the EXE & DLL are compiled with the same (DLL option) run-time library.