Re: [Libguestfs] [PATCH nbdkit 1/8] python: Use PyObject_CallFunction instead of constructing the tuple.
On 11/21/19 10:58 AM, Richard W.M. Jones wrote:
It is unclear why we were constructing this by hand, but using the
following tip we can use PyObject_CallFunction:
https://stackoverflow.com/a/21221335
---
plugins/python/python.c | 17 ++++++-----------
1 file changed, 6 insertions(+), 11 deletions(-)
- r = PyObject_CallObject (fn, args);
+ r = PyObject_CallFunction (fn, "OiLO",
+ obj, count, offset,
+ may_trim ? Py_True : Py_False, NULL);
The use of trailing ', NULL' is appears to be copy-and-paste from my
earlier commit 5ae45c00, where I used it on 3 of the 4 conversions made
there. It is not necessary, nor is it mentioned in the mentioned
stackoverflow link. If you have a format string, a trailing NULL is not
necessary because the format string tells how many varargs to consume;
but with PyObject_CallFunctionObjArgs, a trailing NULL is necessary
because there is no format string and the varargs are parsed as a series
of Python objects until a trailing NULL terminator is encountered.
I've pushed an obvious cleanup patch.
--
Eric Blake, Principal Software Engineer
Red Hat, Inc. +1-919-301-3226
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