How to use await expression?

python python-3.x async-await python-3.5
balki picture balki · Aug 27, 2015 · Viewed 17.6k times · Source

Couldn't figure out how to use await from python 3.5-rc2

>>> async def foo():
...     pass
... 
>>> await foo()
  File "<ipython-input-10-a18cb57f9337>", line 1
    await foo()
            ^
SyntaxError: invalid syntax

>>> c = foo()
>>> await c
  File "<ipython-input-12-cfb6bb0723be>", line 1
    await c
          ^
SyntaxError: invalid syntax

>>> import sys
>>> sys.version
'3.5.0rc2 (default, Aug 26 2015, 21:54:21) \n[GCC 5.2.0]'
>>> del c
RuntimeWarning: coroutine 'foo' was never awaited
>>>

Answer

Railslide picture Railslide · Aug 27, 2015

As per documentation, await can only be used inside a coroutine function. So the correct syntax for using it should be 

async def foo():
    pass

async def bar():
    await foo()

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