Dear all,

I'm constructing a rudimentary webview library for Pharo with UFFI (available here https://github.com/eftomi/Pharo-Webview). For now, the basic things work under Windows. I’m using “a tiny cross-platform webview library“ available at https://github.com/webview/webview.

One of the functions in the dll allows to register a C function to act as a callback and that can be used as a function in javascript, which is convenient for webview presenter - main program communication. This function has the signature:

extern void webview_bind(webview_t w, const char *name,
                              void (*fn)(const char *seq, const char *req,
                                         void *arg),
                              void *arg);

fn is the callback function.

Is there any way to make a ffiCall description of this kind of signature, where fn would be an address of the callback in Pharo?

Thanks and best wishes,
Tomaz

Found the solution! Here it is, if somebody needs the description.

The webview_bind() function in DLL that expects to get a pointer to the function in Pharo can be called like this:

WebViewLibrary >> bind: webview name: aString callback: aFFICallback arguments: aByteString

	^ self ffiCall: #(void webview_bind(void * webview, const char * aString, FFICallback aFFICallback, void * aByteString))

Before doing the actual call, the callback should be made according to fn signature:

doIt := FFICallback 

		signature: #( void (const char *seq, const char *req, void * arg) )

		block: [ :seq :req :arg | 

                        “do the stuff”

		].

And the call is then made as:

WebViewLibrary new bind: webview name: 'newJsFunctionName' callback: doIt  arguments: args.

The next challenge is, of course, threading ...

Best wishes,
Tomaz