[New-bugs-announce] [issue7177] Unclear warning for subprocess.call
report at bugs.python.org
Tue Oct 20 22:20:05 CEST 2009
New submission from Christopher Jefferson <chris at bubblescope.net>:
I wandered across subprocess.call as it was mentioned as a replacement for os.system. The
following large warning is attached to it:
Warning Like Popen.wait(), this will deadlock if the child process generates enough output to a
stdout or stderr pipe such that it blocks waiting for the OS pipe buffer to accept more data.
This scared my off completely, and I assumed the function was simply broken, as I assumed
"stdout pipe" just meant that wherever stdout was sent by default.
I now believe this warning only applies if 'stdout=PIPE', or similar, is used explicitally.
Could this warning be better worded, perhaps adding "if stdout or stderr are explicitly
redirected", as in:
Warning Like Popen.wait(), if stdout or stderr are explicitly redirected this will deadlock if
the child process generates enough output to a stdout or stderr pipe such that it blocks
waiting for the OS pipe buffer to accept more data.
nosy: azumanga, georg.brandl
title: Unclear warning for subprocess.call
versions: Python 3.1
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