Re: subprocess returncode is masked
On Mon, 28 Dec 2009 17:12:23 +0100, Emmanuel wrote: I'm using Python 2.6 and the new subprocess module to get the exit value of an external executable. It appears the return value given by wait() or poll() operations is masked under Unix: I only get the lower 8 bits. So an exit value of 0x0402 in the C program will be seen as 0x02 in Python. And this does not happen on Windows... Any idea why that is ? That's how Unix works. The exit status of a process as reported by wait() (etc) is a 16-bit value (the first Unix systems had a 16-bit int). The top 8 bits (8-15) contain the exit code passed to exit() or returned from main(), truncated to 8 bits. The bottom 7 bits (0-6) contain the signal number if the process was terminated by a signal. Bit 7 is set if the process dumped core. -- http://mail.python.org/mailman/listinfo/python-list
Re: subprocess returncode is masked
On Dec 30, 7:59 pm, Nobody nob...@nowhere.com wrote: On Mon, 28 Dec 2009 17:12:23 +0100, Emmanuel wrote: I'm using Python 2.6 and the new subprocess module to get the exit value of an external executable. It appears the return value given by wait() or poll() operations is masked under Unix: I only get the lower 8 bits. So an exit value of 0x0402 in the C program will be seen as 0x02 in Python. And this does not happen on Windows... Any idea why that is ? That's how Unix works. The exit status of a process as reported by wait() (etc) is a 16-bit value (the first Unix systems had a 16-bit int). The top 8 bits (8-15) contain the exit code passed to exit() or returned from main(), truncated to 8 bits. The bottom 7 bits (0-6) contain the signal number if the process was terminated by a signal. Bit 7 is set if the process dumped core. See also: http://docs.python.org/library/os.html#os.wait -- http://mail.python.org/mailman/listinfo/python-list
Re: subprocess returncode is masked
MRAB wrote : Emmanuel wrote: I'm using Python 2.6 and the new subprocess module to get the exit value of an external executable. It appears the return value given by wait() or poll() operations is masked under Unix: I only get the lower 8 bits. So an exit value of 0x0402 in the C program will be seen as 0x02 in Python. And this does not happen on Windows... Any idea why that is ? I believe that in Unix the exit code is indeed limited to 8 bits. Looks like you're right but the info is difficult to find since it is implementation dependent. I finally found it on http://en.wikipedia.org/wiki/Exit_status. This is very confusing because the parameter type of the exit function is an int ?! -- http://mail.python.org/mailman/listinfo/python-list
Re: subprocess returncode is masked
Emmanuel wrote: MRAB wrote : Emmanuel wrote: I'm using Python 2.6 and the new subprocess module to get the exit value of an external executable. It appears the return value given by wait() or poll() operations is masked under Unix: I only get the lower 8 bits. So an exit value of 0x0402 in the C program will be seen as 0x02 in Python. And this does not happen on Windows... Any idea why that is ? I believe that in Unix the exit code is indeed limited to 8 bits. Looks like you're right but the info is difficult to find since it is implementation dependent. I finally found it on http://en.wikipedia.org/wiki/Exit_status. This is very confusing because the parameter type of the exit function is an int ?! Yes, but the parameter type is a superset of the function's domain. That's not so unusual - consider math.sqrt(), for example. Its parameter type is float, but what happens when you call math.float(-3.5)? regards Steve -- Steve Holden +1 571 484 6266 +1 800 494 3119 PyCon is coming! Atlanta, Feb 2010 http://us.pycon.org/ Holden Web LLC http://www.holdenweb.com/ UPCOMING EVENTS:http://holdenweb.eventbrite.com/ -- http://mail.python.org/mailman/listinfo/python-list
subprocess returncode is masked
I'm using Python 2.6 and the new subprocess module to get the exit value of an external executable. It appears the return value given by wait() or poll() operations is masked under Unix: I only get the lower 8 bits. So an exit value of 0x0402 in the C program will be seen as 0x02 in Python. And this does not happen on Windows... Any idea why that is ? Emmanuel -- http://mail.python.org/mailman/listinfo/python-list
Re: subprocess returncode is masked
On Dec 28, 11:12 am, Emmanuel emmanuel.gau...@pragmadev.com wrote: I'm using Python 2.6 and the new subprocess module to get the exit value of an external executable. It appears the return value given by wait() or poll() operations is masked under Unix: I only get the lower 8 bits. So an exit value of 0x0402 in the C program will be seen as 0x02 in Python. And this does not happen on Windows... Any idea why that is ? Emmanuel -- http://mail.python.org/mailman/listinfo/python-list
Re: subprocess returncode is masked
Emmanuel wrote: I'm using Python 2.6 and the new subprocess module to get the exit value of an external executable. It appears the return value given by wait() or poll() operations is masked under Unix: I only get the lower 8 bits. So an exit value of 0x0402 in the C program will be seen as 0x02 in Python. And this does not happen on Windows... Any idea why that is ? I believe that in Unix the exit code is indeed limited to 8 bits. -- http://mail.python.org/mailman/listinfo/python-list
