Document return value of wait[pid]() more carefully.

Document how to get exit status of a popen() command.
This commit is contained in:
Guido van Rossum 1997-05-09 02:22:59 +00:00
parent e4f347e779
commit 7e691de948
2 changed files with 24 additions and 14 deletions

View File

@ -254,7 +254,10 @@ Open a pipe to or from \var{command}. The return value is an open
file object connected to the pipe, which can be read or written
depending on whether \var{mode} is \code{'r'} (default) or \code{'w'}.
The \var{bufsize} argument has the same meaning as the corresponding
argument to the built-in \code{open()} function.
argument to the built-in \code{open()} function. The exit status of
the command (encoded in the format specified for \code{wait()}) is
available as the return value of the \code{close()} method of the file
object.
(Not on MS-DOS.)
\end{funcdesc}
@ -349,8 +352,8 @@ Execute the command (a string) in a subshell. This is implemented by
calling the Standard C function \code{system()}, and has the same
limitations. Changes to \code{posix.environ}, \code{sys.stdin} etc.\ are
not reflected in the environment of the executed command. The return
value is the exit status of the process as returned by Standard C
\code{system()}.
value is the exit status of the process encoded in the format
specified for \code{wait()}.
\end{funcdesc}
\begin{funcdesc}{tcgetpgrp}{fd}
@ -402,14 +405,16 @@ Set the access and modified time of the file to the given values.
\begin{funcdesc}{wait}{}
Wait for completion of a child process, and return a tuple containing
its pid and exit status indication (encoded as by \UNIX{}).
(Not on MS-DOS.)
its pid and exit status indication: a 16-bit number, whose low byte is
the signal number that killed the process, and whose high byte is the
exit status (if the signal number is zero); the high bit of the low
byte is set if a core file was produced. (Not on MS-DOS.)
\end{funcdesc}
\begin{funcdesc}{waitpid}{pid\, options}
Wait for completion of a child process given by proces id, and return
a tuple containing its pid and exit status indication (encoded as by
\UNIX{}). The semantics of the call are affected by the value of
a tuple containing its pid and exit status indication (encoded as for
\code{wait()}). The semantics of the call are affected by the value of
the integer options, which should be 0 for normal operation. (If the
system does not support \code{waitpid()}, this always raises
\code{posix.error}. Not on MS-DOS.)

View File

@ -254,7 +254,10 @@ Open a pipe to or from \var{command}. The return value is an open
file object connected to the pipe, which can be read or written
depending on whether \var{mode} is \code{'r'} (default) or \code{'w'}.
The \var{bufsize} argument has the same meaning as the corresponding
argument to the built-in \code{open()} function.
argument to the built-in \code{open()} function. The exit status of
the command (encoded in the format specified for \code{wait()}) is
available as the return value of the \code{close()} method of the file
object.
(Not on MS-DOS.)
\end{funcdesc}
@ -349,8 +352,8 @@ Execute the command (a string) in a subshell. This is implemented by
calling the Standard C function \code{system()}, and has the same
limitations. Changes to \code{posix.environ}, \code{sys.stdin} etc.\ are
not reflected in the environment of the executed command. The return
value is the exit status of the process as returned by Standard C
\code{system()}.
value is the exit status of the process encoded in the format
specified for \code{wait()}.
\end{funcdesc}
\begin{funcdesc}{tcgetpgrp}{fd}
@ -402,14 +405,16 @@ Set the access and modified time of the file to the given values.
\begin{funcdesc}{wait}{}
Wait for completion of a child process, and return a tuple containing
its pid and exit status indication (encoded as by \UNIX{}).
(Not on MS-DOS.)
its pid and exit status indication: a 16-bit number, whose low byte is
the signal number that killed the process, and whose high byte is the
exit status (if the signal number is zero); the high bit of the low
byte is set if a core file was produced. (Not on MS-DOS.)
\end{funcdesc}
\begin{funcdesc}{waitpid}{pid\, options}
Wait for completion of a child process given by proces id, and return
a tuple containing its pid and exit status indication (encoded as by
\UNIX{}). The semantics of the call are affected by the value of
a tuple containing its pid and exit status indication (encoded as for
\code{wait()}). The semantics of the call are affected by the value of
the integer options, which should be 0 for normal operation. (If the
system does not support \code{waitpid()}, this always raises
\code{posix.error}. Not on MS-DOS.)