how to call functions from a DLL ?

[ffred]

Hi,
first I'm new to V.. I could have missed something but I search and didn't found something clear telling me how to refer to a specific DLL or how to invoke it.
I found examples calling C functions, like fn C.SetConsoleTitle(title &u16) bool
I can create all the equivalent functions in V like that (I also got a header.h with all the functions) but what I'm missing is the way to tell V to link to my DLL ?
thanks

[JalonSolov]

There are a couple of ways to do this. Either way, you will have to manually convert the pieces you need from your header.h file into V statements for V to understand them (there is no built-in C parser to handle this).

One way is to add #flag windows -l <name of dll without extension> to your V source. If the dll isn't in the current directory, also add #flag windows -L <path to dll>.

The other way is to dynamically load the dll using the dl module functions.

[ffred]

great, thank you !

[Wajinn]

A couple of things that I see in this post, that people might want to be conscious of:

1. I would think a lot of people want to call functions from a DLL and may not have the header or source code.

• So, in this approach, they would want to use dl (https://modules.vlang.io/dl.html).

2. dl appears to only work with 64bit DLLs (for Windows).

If dl doesn't appear to work, the source of the problem might be that the DLL is 32bit and not 64bit. One easy way to verify (in Windows) is to use dependency walker (dependencywalker.com) or dependencies (github.com/lucasg/dependencies), and under CPU. In dependency walker, 64bit will show as x64 and black. If not, will show as x64 and red or as x86. In dependencies, machine, will say amd64 or i386.