Re: [Libusb-devel] how to use function libusb_fill_interrupt_transfer(...)

[Tim R. <ti...@pr...>]

He.David wrote:
>
> Hi, Does anyone can help me to figure out why I got this compiler
> error? How to pass the call back function in this case?
>
>  
>
> voidtransfer_cb_fn (libusb_transfer* transfer){
>
>   cout<<"call back function called"<<endl;
>
> }
>
>  
>
> Void main(…){
>
> …
>
>   libusb_transfer* transfer;
>
>   libusb_fill_interrupt_transfer (transfer, dev_handle, 129, data, 20,
> transfer_cb_fn,  user_data, 10000);
>
>  
>
> }
>
>  
>
> Error message:
>
> error C2664: 'libusb_fill_interrupt_transfer' : cannot convert
> parameter 6 from 'void (__cdecl *)(libusb_transfer *)' to
> 'libusb_transfer_cb_fn'
>
> 2>        None of the functions with this name in scope match the
> target type
>

Try declaring it as C linkage:

    extern "C" void cb_fn( libusb_transfer* transfer );

-- 
Tim Roberts, ti...@pr...
Providenza & Boekelheide, Inc.