strange behavior in python
- by fsm
The tags might not be accurate since I am not sure where the problem is.
I have a module where I am trying to read some data from a socket, and write the results into a file (append) It looks something like this, (only relevant parts included)
if __name__ == "__main__":
<some init code>
for line in file:
t = Thread(target=foo, args=(line,))
t.start()
while nThreads > 0:
time.sleep(1)
Here are the other modules,
def foo(text):
global countLock, nThreads
countLock.acquire()
nThreads += 1
countLock.release()
"""connect to socket, send data, read response"""
writeResults(text, result)
countLock.acquire()
nThreads -= 1
countLock.release()
def writeResults(text, result):
"""acquire file lock"""
"""append to file"""
"""release file lock"""
Now here's the problem. Initially, I had a typo in the function 'foo', where I was passing the variable 'line' to writeResults instead of 'text'. 'line' is not defined in the function foo, it's defined in the main block, so I should have seen an error, but instead, it worked fine, except that the data was appended to the file multiple times, instead of being written just once, which is the required behavior, which I got when I fixed the typo.
My question is,
1) Why didn't I get an error?
2) Why was the writeResults function being called multiple times?
