[Pyrex] Pyrex doesn't recognize a declared variable...

[Brian Myers]

I'm trying to wrap the decNumber library with Pyrex and have had  
pretty good success so far. There's only one last problem showing up.
I have an extension class defined like this:

In a .pxd file:
cdef extern from "decNumber.h":
     ctypedef struct decNumber:
         int32_t digits          #/* Count of digits in the  
coefficient; >0 */
         int32_t exponent        #/* Unadjusted exponent, unbiased,  
in */
         #/* range: -1999999997 through 999999999 */
         uint8_t bits            #/* Indicator bits (see above) */
         char *lsu

In a .pyx file:
     cdef class oetl_decimal:
     .
     .
     .
         cdef void set_buffer(self, decNumber *buffer):
             if buffer[0].digits > self.context.ctx.digits:
                 raise InvalidOperation("Context precision is too low  
to set buffer.")
             decNumberRescale(self.buffer, buffer,  
self.context.decScale, &self.context.ctx)
             self.context.c_assert()
     .
     .
     .
         def normalized(self):
             cdef decNumber *tmp
             tmp = <decNumber *> alloca(128)
             decNumberNormalize(tmp, self.buffer, &self.context.ctx)
             self.context.c_assert()
             res = oetl_decimal(self.context)
             res.set_buffer(tmp)
             return res

     When I compile, Pyrex complains in the call to res.set_buffer 
(tmp) above that it can't convert a decNumber (*) to a python object.  
But tmp is cdef'ed as a decNumber * and set_buffer is cdef'ed to  
accept a decNumber * as its second parameter.

     Am I doing something stupid and obvious here? I've tried a  
couple of things, including looking at the generated code (which  
looks OK to me), and discovered that Pyrex seems to know tmp is a  
decNumber *. It doesn't seem to realize the set_buffer's second  
argument is a decNumber *.

     Any help appreciated

Brian