FFI: Passing argv

steve64

I have a DLL with an exported function with signature:
bool lib_initialise(int argc, char **argv);

What is the correct binding for LuaRT ? Is the following ok?
mydll.lib_initialise = '(ip)B'

Since I do not need to pass any specific argument,
what is the syntax to call lib_initialise() passing argc=0 and argv=null?

Samir

Yes it's the correct definition.
You call it using mydll.lib_initialise(0, c.NULL)

steve64

Tried but does not work, in the sense that the control is lost inside the mydll.lib_initialise(0, c.NULL) call (no return).
So I would like to try to pass a couple of string arguments, could you help me in showing a simple syntax example for that?
mydll.lib_initialise(2, ???)

Samir

This should work :

local c = require "c"

-- load library
local mydll = c.Libray("my.dll")

-- declare init C function
mydll.lib_initialise = '(ip)B'

-- declare a C array of 2 strings (char*)
local ArgvArray = c.Array("Z", 2) 

-- Create a ArgvArray and initialize it
local argv = ArgvArray {
    "First argument",
    "Second argument"
}

-- Call the init function
mydll.lib_initialise(2, c.Pointer(argv))

steve64

local ArgvArray = c.Array("Z", 2)
give error --> bad argument #2 in method 'Array.constructor' (invalid option 'Z')

Samir

Yes it's a bug, Array types should use the same convention as of Library function definition.
For now you can use c.Array("z", 2) instead