I did manage to look at a block of data looking bytes by
adding a printf of gbuffer after CFRunLoopRun();
now what I need to know is, how do I read several blocks??
In the synchronous case, I did a for loop around readpipe.
In the asynchronous case, how do I need to modify the code
to get several blocks of data, instead of just one?
thanks
Anne
On Thu, 11 Aug 2005, Anne G wrote:
> I have been able to read data with ReadPipe, but I am not
> sure I am getting all the data, and in any case, I am told
> I need to learn asynchronous reading for my application.
>
> I think I did the same as some folks on this list: I took
> the USBSimpleExample and tried to adapt it for an
> asynchronous read.
>
> I am imitating without any understanding. In my program
> the last argument of ReadPipeAsync is inpipe, in another
> err. What should it be in my case?
>
> I get no error, and one printout from mycallBackFunction,
> but whatever it is being printed out, it does not look like
> data: I guess my data should be in gbuffer.
>
> Where and when do I access my data?
>
> thanks
>
> anne
> ----------------------------------------------------
>
> MyCallBackFunction(void *dummy, IOReturn result, void *arg0)
> {
> printf("MyCallbackfunction: %d, %d, %d\n", (int)dummy,
> (int)result, (int)arg0);
> CFRunLoopStop(CFRunLoopGetCurrent());
> }
>
> void transferData(IOUSBInterfaceInterface **intf, UInt8
> inPipeRef)
> {
> IOReturn err;
> CFRunLoopSourceRef cfSource;
> int i;
>
> char gBuffer[8];
> UInt32 numBytesRead;
>
> numBytesRead = sizeof(gBuffer);
>
> err = (*intf)->CreateInterfaceAsyncEventSource(intf,
> &cfSource);
> if (err)
> {
> printf("transferData: unable to create event source,
> err = %08x\n", err);
> return;
> }
> CFRunLoopAddSource(CFRunLoopGetCurrent(), cfSource,
> kCFRunLoopDefaultMode);
> printf("Asynchronous event source added to run
> loop\n");
>
> err = (*intf)->ReadPipeAsync(intf, inPipeRef,
> gBuffer, numBytesRead, (IOAsyncCallback1)MyCallBackFunction,
> (void*)(UInt32)inPipeRef);
> if (err != kIOReturnSuccess)
> {
> printf("Unable to perform asynchronous bulk read
> (%08x)\n", err);
> CFRunLoopRemoveSource(CFRunLoopGetCurrent(),
> cfSource, kCFRunLoopDefaultMode);
> return;
> }
>
> printf("transferData: calling CFRunLoopRun\n");
> CFRunLoopRun();
> printf("transferData: returned from CFRunLoopRun\n");
> CFRunLoopRemoveSource(CFRunLoopGetCurrent(), cfSource,
> kCFRunLoopDefaultMode);
>
> }
>
>
>
>
>
>
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