[Python-Dev] cpython: Issue #18571: Implementation of the PEP 446: file descriptors and file handles (original) (raw)

Georg Brandl g.brandl at gmx.net
Sun Sep 15 10:34:04 CEST 2013

On 08/28/2013 01:20 AM, victor.stinner wrote:

http://hg.python.org/cpython/rev/ef889c3d5dc6 changeset: 85420:ef889c3d5dc6 user: Victor Stinner <victor.stinner at gmail.com> date: Wed Aug 28 00:53:59 2013 +0200 summary: Issue #18571: Implementation of the PEP 446: file descriptors and file handles are now created non-inheritable; add functions os.get/setinheritable(), os.get/sethandleinheritable() and socket.socket.get/setinheritable().

+.. fdinheritance: + +Inheritance of File Descriptors +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +A file descriptor has a inheritable flag which indicates if the file descriptor +can be inherited or not in child processes. Since Python 3.4, file descriptors +created by Python are non-inheritable by default. + +On UNIX, non-inheritable file descriptors are closed in child processes at the +execution of a new program, other file descriptors are inherited. + +On Windows, non-inheritable handles and file descriptors are closed in child +processes, except standard streams (file descriptors 0, 1 and 2: stdin, stdout +and stderr) which are always inherited. Using :func:os.spawn* functions, +all inheritable handles and all inheritable file descriptors are inherited. +Using the :mod:subprocess module, all file descriptors except standard +streams are closed, inheritable handles are only inherited if the closefds +parameter is False. + +.. versionadded:: 3.4 + +.. function:: getinheritable(fd) + + Get the inheritable flag <fdinheritance> of the specified file + descriptor. Return a :class:bool. + +.. function:: setinheritable(fd, inheritable) + + Set the inheritable flag <fdinheritance> of the specified file descriptor. + +.. function:: gethandleinheritable(handle) + + Get the inheritable flag <fdinheritance> of the specified handle. Return a :class:bool. + + Availability: Windows. + +.. function:: sethandleinheritable(handle, inheritable) + + Set the inheritable flag <fdinheritance> of the specified handle. + + Availability: Windows. +

"Handle" is used nowhere else in the os module documentation. Do you think it would make sense to have a brief paragraph on what are possible handles under Windows (and that file descriptors aren't handles)?

Georg

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