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authorFred Drake <fdrake@acm.org>2001-09-11 19:56:51 (GMT)
committerFred Drake <fdrake@acm.org>2001-09-11 19:56:51 (GMT)
commit098d7fae39fea0adc976edb7c1060054be4b467e (patch)
treec2dc4ab6d15d51f9b5b45fa6c9221486968025e4
parent7b07a41e9f078065b966a2414a24c0e5b7889ef7 (diff)
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Document clearly that the only way to retrieve the return code from the
child processes is to use the Popen3 and Popen4 classes. This fixes SF bug #460512.
-rw-r--r--Doc/lib/libos.tex6
-rw-r--r--Doc/lib/libpopen2.tex7
2 files changed, 13 insertions, 0 deletions
diff --git a/Doc/lib/libos.tex b/Doc/lib/libos.tex
index 16f3690..1c3a584 100644
--- a/Doc/lib/libos.tex
+++ b/Doc/lib/libos.tex
@@ -315,6 +315,12 @@ specified, it specifies the buffer size for the I/O pipes.
objects should be opened in binary or text mode. The default value
for \var{mode} is \code{'t'}.
+These methods do not make it possible to retrieve the return code from
+the child processes. The only way to control the input and output
+streams and also retrieve the return codes is to use the
+\class{Popen3} and \class{Popen4} classes from the \refmodule{popen2}
+module; these are only available on \UNIX.
+
\begin{funcdesc}{popen2}{cmd\optional{, mode\optional{, bufsize}}}
Executes \var{cmd} as a sub-process. Returns the file objects
\code{(\var{child_stdin}, \var{child_stdout})}.
diff --git a/Doc/lib/libpopen2.tex b/Doc/lib/libpopen2.tex
index add0af1..8cdf0f5 100644
--- a/Doc/lib/libpopen2.tex
+++ b/Doc/lib/libpopen2.tex
@@ -24,6 +24,13 @@ this is needed to determine whether the file objects should be opened
in binary or text mode. The default value for \var{mode} is
\code{'t'}.
+The only way to retrieve the return codes for the child processes is
+by using the \method{poll()} or \method{wait()} methods on the
+\class{Popen3} and \class{Popen4} classes; these are only available on
+\UNIX. This information is not available when using the
+\function{popen2()}, \function{popen3()}, and \function{popen4()}
+functions, or the equivalent functions in the \refmodule{os} module.
+
\begin{funcdesc}{popen2}{cmd\optional{, bufsize\optional{, mode}}}
Executes \var{cmd} as a sub-process. Returns the file objects
\code{(\var{child_stdout}, \var{child_stdin})}.