Passing Named Paramater To A C Func?

[John Abel]

Hi,

Thanks for that, its pointed me in the right direction.

Regards

John

Fredrik Lundh wrote:

>John Abel wrote:
>
>  
>
>>I'm writing a C function, which will have a Python wrapper, and I wish
>>to be able to pass it an optional, named parameter.  For example:
>>
>>def funcName( dirName, fileName=None ):
>>
>>   if fileName is None:
>>       Some Other Stuff
>>
>>   cCall( dirName, fileName )
>>
>>Is the best to handle this in the Python wrapper, or is there a way of
>>handling these via C.  None of the extending documents seem to mention
>>anything about this.
>>    
>>
>
>to handle named arguments on the C level, use ParseTupleAndKeywords.
>here's an example, taken from the regular expression engine:
>
>static PyObject*
>pattern_match(PatternObject* self, PyObject* args, PyObject* kw)
>{
>    ...
>
>    PyObject* string;
>    int start = 0;
>    int end = INT_MAX;
>    static char* kwlist[] = { "pattern", "pos", "endpos", NULL };
>    if (!PyArg_ParseTupleAndKeywords(args, kw, "O|ii:match", kwlist,
>                                     &string, &start, &end))
>        return NULL;
>
>you also have to set the METH_KEYWORDS flag in the PyMethodDef
>table:
>
>static PyMethodDef pattern_methods[] = {
>    {"match", (PyCFunction) pattern_match, METH_VARARGS|METH_KEYWORDS},
>    ...
>
>:::
>
>in your case, I'm not sure it's really worth the effort, since you
>need to look at the argument at the Python level anyway.
>
></F>
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