[Python-Dev] Constants from C headers and int/long unification

[Guido van Rossum]

> I have C header files which I parse and to which I can do some simple 
> processing before outputting them as Python code. An example C file 
> will contain
> 
> enum {
>     kConstantOne = 0xffffffff,
>     kConstantTwo = -1,
> };
> 
> Regexps will grab the two constants and output them to Python. The 
> Python programmer will pass these constants to an API routine, at which 
> point I need a PyArg_Parse format char that will convert both of these 
> values to the 32 bit pattern 0xffffffff.
> 
> Question 1: Do I need to add anything to the constants before 
> outputting them as Python code?

No -- kConstantTwo automatically become a long with value 2**32-1 in
Python 2.3 and up.

> Question 2: Is there a format char that will convert both of the values 
> produced by the answer to question 1 to the 32 bit pattern 0xffffffff?

If you mean a PyArg_Parse format char, yes: use 'k'.

If you meant a Python % format char, you'd have to write "%x" % (x&0xffffffff).

--Guido van Rossum (home page: http://www.python.org/~guido/)