[Python编程(第4版)].(Programming.Python.4th.Edition).Mark.Lutz.文字版

>>> pipe.read()

'Bye sys world\012'

>>> stat = pipe.close() # returns exit code

>>> stat

10752

>>> hex(stat)

'0x2a00'

>>> stat >> 8 # extract status from bitmask on Unix-likes

42

>>> pipe = os.popen('python testexit_os.py')

>>> stat = pipe.close()

>>> stat, stat >> 8

(25344, 99)

This code works the same under Cygwin Python on Windows. When using os.popen
on such Unix-like platforms, for reasons we won’t go into here, the exit status is actually
packed into specific bit positions of the return value; it’s really there, but we need to
shift the result right by eight bits to see it. Commands run with os.system send their
statuses back directly through the Python library call:

>>> stat = os.system('python testexit_sys.py')

Bye sys world

>>> stat, stat >> 8

(10752, 42)

>>> stat = os.system('python testexit_os.py')

Bye os world

>>> stat, stat >> 8

(25344, 99)

All of this code works under the standard version of Python for Windows, too, though
exit status is not encoded in a bit mask (test sys.platform if your code must handle
both formats):

C:\...\PP4E\System\Exits> python

>>> os.system('python testexit_sys.py')

Bye sys world

42

>>> os.system('python testexit_os.py')

Bye os world

99

>>> pipe = os.popen('python testexit_sys.py')

>>> pipe.read()

'Bye sys world\n'

>>> pipe.close()

42

>>>

>>> os.popen('python testexit_os.py').close()

99

Program Exits | 217