how to know argument name with which a function of extended c called

[Arnaud Delobelle]

rahul <rahul03535 at gmail.com> writes:

> Hi,
>   i need to write a 'c extension function' in this function i need to
> change argument value with  which this function called.
>   ie,
>          if a python code like
>             import changeValue as c
>             arg="old value"
>             c.changeValue(arg)
>             print arg
>
>  then it print "new value"
>
>  i write code like this..
>
> static PyObject *changeValue(PyObject *self,PyObject *args){
>         PyObject *sampleObj, *m ;
> 	char *argName;
>
>       if (!PyArg_ParseTuple(args, "O", &sampleObj)){
>                 return NULL;
>       }
>
>    m = PyImport_AddModule("__main__");
>    PyObject_SetAttrString(m, argName, "new value");
>    return Py_BuildValue("");
> }
>
> But for this i need to know the argument name with which this function
> called .
> Is this possible to know argument name in extended c function? if yes,
> than how i can do it???

No, you can't and it's a good thing, because when reading your code you
can find out very easily when a variable has been rebound: it's on those
lines of the form

    name = expression

Instead, make your 'changeValue" function return the new value, then
write:

import changeValue as c
arg = "old value"
arg = c.changeValue(arg)
print arg

It'll work, with the added benefit that it'll be clearer that arg was
changed.

-- 
Arnaud