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In the Python API, how can I redirect the output of an asynchronous function call of a function without return value?

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I am using the Python API and I want to redirect the output of an asynchronously called function without return value. Is this maybe impossible?
My Python Script looks a little bit like this:
import matlab.engine as eng
import StringIO
out = StringIO.StringIO()
MAT = eng.start_matlab()
ret = MAT.func('arg', async=True, nargout=0, stdout=out)
while not ret.done() : pass
print out.getvalue()
MAT.quit()
When running this script, there is only a line feed / carriage return printed. The return value of
ret.result()
is "None".

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Accepted Answer

Bo Li
Bo Li on 16 Feb 2017
What about adding "ret.result()" before printing the output buffer like following?
while not ret.done() : pass
ret.result()
print out.getvalue()

  3 Comments

Esteban Henriques
Esteban Henriques on 11 May 2018
From:
def result(self, timeout=None):
in fevalfuture.py, it seems that it is not possible to get any feedback from the out stream until the call is done. Doesn't this at least in part defeat the purpose of an async call?
Sven-Eric Krüger
Sven-Eric Krüger on 14 May 2018
@Esteban MATLAB itself is always single threaded, but you can asyncronuously call functions. So the Python Script will not hold on the call of the MATLAB Engine, but continue. The MATLAB Interpreter does his stuff on his own and so does the Python Interpreter.

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