At 9:54 -0700 28/6/04, Krishna Monian wrote: When I define a function that is going to be called as a result of an IOConnectMethodScalarIStructureO are there any restrictions on the parameters the function has to take? Yes. Your input parameters must be a sequence of scalars and your output parameters must a contiguous block of memory. That's the meaning of "ScalarI" (scalar in) and "StructureO" (structure out) respectively. Of course, there are other IOConnectMethod routines for the other permutations. I want to pass in a char** from user-space(memory already allocated) to kernel space, and copy some data into it. It's generally best if you embed your data in a parameter block and pass back the data using a "StructureO" routine. That's the approach that will yield the best long term compatibility. However, you can, if necessary, pass a pointer in from user space as a scalar parameter, create a memory descriptor from that pointer (make sure you use a routine that takes a "withTask" parameter, so you can specify the address space for the memory), and transfer data to that.

From your other posts it seems like you're working deep in the kernel. If so, perhaps using I/O Kit for this is the wrong approach. There may be a more appropriate mechanism for you to transfer data to user space (sysctl, ioctl, a driver, copyin/out, and so on).

S+E -- Quinn "The Eskimo!" <http://www.apple.com/developer/> Apple Developer Technical Support * Networking, Communications, Hardware _______________________________________________ darwin-kernel mailing list | darwin-kernel@lists.apple.com Help/Unsubscribe/Archives: http://www.lists.apple.com/mailman/listinfo/darwin-kernel Do not post admin requests to the list. They will be ignored.