Please help with Threading

[Cameron Simpson]

On 20May2013 10:53, Carlos Nepomuceno <carlosnepomuceno at outlook.com> wrote:
| I just got my hands dirty trying to synchronize Python prints from many threads.
| Sometimes they mess up when printing the newlines. 
| I tried several approaches using threading.Lock and Condition.
| None of them worked perfectly and all of them made the code sluggish.

Show us some code, with specific complaints.

Did you try this?

  _lock = Lock()

  def lprint(*a, **kw):
    global _lock
    with _lock:
      print(*a, **kw)

and use lprint() everywhere?

For generality the lock should be per file: the above hack uses one
lock for any file, so that's going to stall overlapping prints to
different files; inefficient.

There are other things than the above, but at least individual prints will
never overlap. If you have interleaved prints, show us.

| Is there a 100% sure method to make print thread safe? Can it be fast???

Depends on what you mean by "fast". It will be slower than code
with no lock; how much would require measurement.

Cheers,
-- 
Cameron Simpson <cs at zip.com.au>

My own suspicion is that the universe is not only queerer than we suppose,
but queerer than we *can* suppose.
        - J.B.S. Haldane "On Being the Right Size"
          in the (1928) book "Possible Worlds"