Path: csiph.com!usenet.pasdenom.info!news.albasani.net!newsfeed.freenet.ag!news2.euro.net!newsgate.cistron.nl!newsgate.news.xs4all.nl!post.news.xs4all.nl!not-for-mail
MIME-Version: 1.0
In-Reply-To: <87a9yt7bw6.fsf@handshake.de>
References: <CA+WuaScBDU_5LcrCrTtDr6N3gHCk9hQ03fA=DT359GCRY=a=KQ@mail.gmail.com> <CA+WuaSeRExxaD9yCNWhXoWqsV_ZqP8DOvdErMRdNS-H_UtzQyg@mail.gmail.com> <87a9yt7bw6.fsf@handshake.de>
Date: Sat, 21 Jul 2012 10:11:30 -0600
Subject: Re: A thread import problem
From: Bruce Sherwood <bruce.sherwood@gmail.com>
To: python-list@python.org
Content-Type: text/plain; charset=ISO-8859-1
Precedence: list
Newsgroups: comp.lang.python
Message-ID: <mailman.2387.1342887093.4697.python-list@python.org>
Lines: 59
NNTP-Posting-Host: 2001:888:2000:d::a6
Xref: csiph.com comp.lang.python:25748

I couldn't get a simple test case to work. I append a listing of the
little test files, all in the same folder. The diagnostic statement
print('after start_new_thread\n') works, but then nothing. Originally
I tried importing testABA.py but was worried that the circular
importing (A imports B which imports A) would be a problem, hence the
test of importing a version of the test program without the import.

The failure of this test case suggests that one cannot do imports
inside secondary threads started in imported modules, something I keep
tripping over. But I hope you'll be able to tell me that I'm doing
something wrong!

Incidentally, a simple test is to execute the file ABA.py, in which
case everything works.

Bruce Sherwood

---------------------------
testABA.py -- execute this file

from ABA import *
print('exec testABA')
from math import sin
print(sin(3.14159/6))

----------------------------
testABA_noimport.py -- a version of testABA.py without the import of ABA

print('exec testABA_noimport')
from math import sin
print(sin(3.14159/6))

-----------------------------
ABA.py

from thread import start_new_thread
from time import sleep
import sys

user = 'testABA_noimport'
start_new_thread(lambda: __import__(user), ())
print('after start_new_thread\n')

while True:
    sleep(1)

On Sat, Jul 21, 2012 at 2:32 AM, Dieter Maurer <dieter@handshake.de> wrote:
> The usual approach to this situation is to invoke the user code via
> a callback from the UI main loop or invoke it explicitely
> after the UI system has been set up immediately before its main loop
> is called. Might look somehow like this:
>
> main thread:
>
> from thread import start_new_thread
> from visual import setup_gui, start_main_loop
> setup_gui() # sets up the GUI subsystem
> start_new_thread(lambda: __import__(<your module>), ())
> start_main_loop()