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To: python-list@python.org
From: Ned Batchelder <ned@nedbatchelder.com>
Subject: Re: how avoid delay while returning from C-python api?
Date: Wed, 28 May 2014 06:57:09 -0400
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On 5/28/14 6:22 AM, Lakshmipathi.G wrote:
> Hi -
>
> I have C-Python api like below.  It works fine, but the problem is
> while invoking this method
> from python script say
>
> #cat script.py
> <snip>
> offset=0
> size=4
> write_object(offset,size)
> </snip>
>
>
> This calls write_this_c() C api and returns quickly to next printf statement.
> But the return call (Py_RETURN_NONE) takes something like 4-6 seconds.
>
> -----
> static
> PyMethodDef xyz_methods[] = {
> {"write_object", write_object, METH_VARARGS,"write some stuff "},
> {NULL, NULL, 0, NULL}
> };
>
>
> ----
> static PyObject *
> write_object(PyObject *self, PyObject *args)
> {
>          int offset, size;
>          if (!PyArg_ParseTuple(args,"ii", &offset, &size))
>                  Py_RETURN_NONE;
>
>          printf("before call");
>          write_this_c(offset, size);
>          printf("after call");
>          Py_RETURN_NONE;          ##delay happens here
> }
>
> How to avoid this delay time? Thanks for any help/pointers!

It can't be as simple as the Py_RETURN_NONE taking 4-6 seconds: hundreds 
of built-in functions in Python are coded exactly this way, and they 
don't have a delay on return.  Something else is going on.

How did you determine that it was the return that was taking the time?


>
>
> ----
> ----
> Cheers,
> Lakshmipathi.G
> FOSS Programmer.
> www.giis.co.in
>


-- 
Ned Batchelder, http://nedbatchelder.com