access to preallocated block of memory?

[Neil Hodgson]

Greg Copeland:

> I already have access to the block on memory...I
> simply need information about existing python facilities which will
> allow me to expose the block to python as a native type...from which I
> can read byte for byte and optionally write to.  As I originally said,
> I have a pointer and the block's length.  I have access to it already.
> I simply need to expose it to python.  What facilities already exist to
> allow this which do not cause malloc/memcpy on said block?

    There is no generic array.at(address,length) in core Python as it 
would be a hole in Python's type system, allowing reading from or 
writing to any memory location and thus making it easier for Python to 
cause memory corruption and crashes. Libraries such as ctypes or its 
predecessor calldll do allow such access on some operating systems but 
not VxWorks. It would be quicker to write a special-purpose library for 
your job rather than port ctypes.

    Neil