[Pyrex] Pyrex questions

[Greg Ewing]

Tom Kobialka <u3356514 at anu.edu.au>:

> Is there a searchable online mailing list archive available for 
> Pyrex?

No, there isn't, sorry.

> I am encapsulating a small C program that makes use of a very specific
> gravitational wave frame library. I want to call the routines in the
> library from my C program. Do I have to encapsulate the library in
> Pyrex in order to call it from my encapsulated C program?

I'm a bit confused about what you're trying to do. If the
gravitational wave library is only called through your C code, and
never directly from Python, you should only have to wrap your C code,
i.e.

  Python -> Pyrex wrapper for your C code -> your C code -> Library

> it doesn't seem to mention C routines and procedures such as atoi,
> malloc, opendir (dirent.h), casting or nesting i.e monkey = (char *)
> malloc(strlen(banana) + strlen(paddlepop->chocolate))

Any C routine can be called from Pyrex if you declare it appropriately
in a 'cdef extern from' block; see the section on "Interfacing with
External C Code". Casting is possible, bit with a slightly different
syntax; see "Differences between C and Pyrex expression syntax".

Your example would be translated into Pyrex as follows:

  cdef extern from "stdlib.h":
    void *malloc(int len)

  cdef extern from "string.h":
    int strlen(char *)

  # suitable definitions here for monkey, banana,
  # paddleop and chocolate

  monkey = <char *> malloc(strlen(banana) +
    strlen(paddlepop.chocolate))

> Does anyone have a small sized (300 + line) C program and
> corresponding pyrex code

Have you looked at Michael's Quick Guide to Pyrex? It contains
a couple of examples of wrapping real-world C libraries.

Greg Ewing, Computer Science Dept, +--------------------------------------+
University of Canterbury,	   | A citizen of NewZealandCorp, a	  |
Christchurch, New Zealand	   | wholly-owned subsidiary of USA Inc.  |
greg at cosc.canterbury.ac.nz	   +--------------------------------------+