@doofenstein
Right, I forgot the {.cdecl.}, good catch.
The reason why the cast is there, is that the iup library has only one function
to set the callbacks, which in `Nim` is:
# Callback definition
Icallback* = proc (arg: PtrIhandle): cint {.cdecl.}
# Function for setting a callback
proc setCallback*(ih: PtrIhandle, name: cstring, fn: Icallback): Icallback
{.importc: "IupSetCallback",
cdecl, discardable.}`
Run
and in `C` it's:
// Callback definition
typedef int (*Icallback)(Ihandle*);
// Function for setting a callback
Icallback IupSetCallback(Ihandle* ih, const char *name, Icallback func);
Run
Which works great for callbacks that have the exact same signature as
Icallback. But some callbacks have additional parameters! And in `C` example
code for the library they just cast the different callback signatures with
`(Icallback)`. Example from the IUP official docs:
// Functions
int btn_on_off_cb(Ihandle *self)
{
// code
}
int btn_image_button_cb( Ihandle *self,int b, int e )
{
// code
}
// Setting up the callbacks
IupSetCallback( btn_on_off, "ACTION", (Icallback) btn_on_off_cb );
IupSetCallback( btn_image, "ACTION", (Icallback) btn_image_button_cb );
Run
So I'm just doing the same as these examples in `C`, because I don't know of a
way to do this better in `Nim`. Any suggestions would be greatly appreciated?
