[Pyrex] "Language Overview" confusion

[David Goldsmith]

Hi, newbie here!  From the "Referencing C header files" section of the LO:

"It's important to understand that Pyrex does /not/ itself read the C 
header file, so you still need to provide Pyrex versions of any 
declarations from it that you use."

As a newbie, I have no idea what the second part of this sentence means: 
"provide Pyrex versions of any declarations" - where (i.e., in which 
file)?  What do these look like? 

(By implication, the previous example:

    cdef extern from "spam.h":

        int spam_counter

        void order_spam(int tons)

(which goes in the .pyx file, yes?) is *not* such a declaration, but no 
positive example of such a declaration appears to be given, at least not 
at that place in the LO, and it is not clear in which file said 
declaration should go).

Please explain.  Thanks!

DG
-- 
ERD/ORR/NOS/NOAA <http://response.restoration.noaa.gov/emergencyresponse/>