Improved struct module

[Jeremy Hylton]

>>>>> "RB" == Robin Boerdijk <robin.boerdijk at nl.origin-it.com> writes:

  RB> I do want to come back on the buffer interface though. I think I
  RB> have no alternative for using it. How else can I encapsulate a C
  RB> API function that expects a pre-allocated buffer as a parameter.

  RB> For example, how could I encapsulate the following C function:

  RB>     int GetMessageFromQueue(void* buffer, int bufsize);

  RB> where buffer is an application supplied buffer of size
  RB> bufsize. The function will return the part of the buffer
  RB> actually filled. The only one who knows what a reasonable size
  RB> of the buffer is is the application programmer (who is
  RB> programming in Python).

This sounds a lot like the recv method on sockets.

The C API to recv is:

     ssize_t recv(int socket, void *buffer, size_t length,
          int flags);

The Python program calls the recv method on a socket and passes a
buffer size (call the arg buflen).

The C implementation of the recv method is pretty simple:
1. Allocate a string of size buflen.
2. Call recv and pass the Python string's ob_sval as the buffer
   argument.
3. Check how many bytes were actually returned and Resize the string
   to that size.

Jeremy