How to call C function in shared library?

[Kalle Svensson]

Sez Oleg Krivosheev:
> i already have shared library
> with simple function which takes double
> and returns double. Is it simple way 
> to call it directly from Python?

You could take a look at SWIG (http://www.swig.org/), or make your own
wrapper.  Something like (extremely untested):

/************  BEGIN **************/
#include "Python.h"
#include "myheader.h"

static PyObject *
wrap_myfunction(PyObject *self, PyObject *args)
{
    double arg, ret;
    if (!PyArg_ParseTuple(args, "d", &arg))
        return NULL;
    ret = myfunction(arg);
    return Py_BuildValue("d", ret);
}

/* Module initialisation stuff goes here...     */
/* Check http://www.python.org/doc/current/ext/ */
/* and http://www.python.org/doc/current/api/   */
/* for more information...                      */
/************  END **************/

> Or some python encapsulation for dlopen/dlsym/dlclose ?

There is the dl module:
http://www.python.org/doc/current/lib/module-dl.html

Peace,
  Kalle
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