Hello,

This has actually nothing to do with memoryview:

"""
>>> import os
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>>> stdin = os.fdopen(0)
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>>> del stdin
__main__:1: ResourceWarning: unclosed file <_io.TextIOWrapper name=0 mode='r' encoding='UTF-8'>
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>>> 
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"""

When the object returned by os.fdopen() is garbage collected, the underlying FD is closed, and the interpreter aborts when it tries to read from stdin.
So it's not an issue, try calling memoryview(fdopen(<any FD other than 0,1,2>) and it'll work.