On 23/11/2017 11:35 AM, Skuzzi wrote:
Hi, I am new to D and I want to use it to create some tools that call
certain functions from the process of a game, using an injected DLL
written in D. I have reverse engineered the addresses and arguments of
the function. Typically this kind of stuff is done with C++ and almost
all the available resources online focus on C++. I was not able to find
anything specific to this done in D.
This is what a function prototype might look like in C++:
typedef void (__stdcall* _function) (const char *text);
_function function;
alias _function = extern(C) void function(const(char)* text);
_function myFunction;
Which you would then call using the address of the function in memory:
function = (_function)(ADDRESS_OF_FUNCTION);
function("Some text");
void* ADDRESS_OF_FUNCTION = ...;
myFunction = cast(_function)ADDRESS_OF_FUNCTION;
myFunction(cast(const(char)*("Some text".ptr));
Literals have a \0 at the end so this is safe.
I want to do this in D. I understand that D uses "extern (C)" and does
away with specifying calling conventions. However, how does D know the
calling convention required? What if it is a __thiscall or something
else, will it always be handled properly by D, just be specifying
"extern (C)"?
extern takes care of calling conventions and mangling for declarations
(which you are not using in the above).
See[0] point 3 regarding how this all works.
[0] https://dlang.org/spec/interfaceToC.html#calling_c_functions
