Question

I couldn’t find anything useful on the MSDN for this case. Using Dependency Walker, in the module list, I see a mixed usage of Console and GUI.

Does this have an impact when compiling a DLL?

Answer 1

This option only has an effect on applications (exe), not on libraries(dll).

Its documentation says:

The /SUBSYSTEM option specifies the environment for the executable.

The choice of subsystem affects the entry point symbol (or entry point
function) that the linker will select.

This does not affect libraries, which have their own (optional) entry point.

Additional information following CyberShadow’s comment: The subsystem field itself seems to be ignored when a DLL is loaded. This article about CSRSS says (emphasis mine):

Furthermore, each process is associated with one, certain subsystem;
this property is being set by the linker (during the compilation
process), and resides in the following PE structure field: […]