popen2.py 文件源码

def __init__(self, cmd, capturestderr=False, bufsize=-1):
        """The parameter 'cmd' is the shell command to execute in a
        sub-process.  On UNIX, 'cmd' may be a sequence, in which case arguments
        will be passed directly to the program without shell intervention (as
        with os.spawnv()).  If 'cmd' is a string it will be passed to the shell
        (as with os.system()).   The 'capturestderr' flag, if true, specifies
        that the object should capture standard error output of the child
        process.  The default is false.  If the 'bufsize' parameter is
        specified, it specifies the size of the I/O buffers to/from the child
        process."""
        _cleanup()
        self.cmd = cmd
        p2cread, p2cwrite = os.pipe()
        c2pread, c2pwrite = os.pipe()
        if capturestderr:
            errout, errin = os.pipe()
        self.pid = os.fork()
        if self.pid == 0:
            # Child
            os.dup2(p2cread, 0)
            os.dup2(c2pwrite, 1)
            if capturestderr:
                os.dup2(errin, 2)
            self._run_child(cmd)
        os.close(p2cread)
        self.tochild = os.fdopen(p2cwrite, 'w', bufsize)
        os.close(c2pwrite)
        self.fromchild = os.fdopen(c2pread, 'r', bufsize)
        if capturestderr:
            os.close(errin)
            self.childerr = os.fdopen(errout, 'r', bufsize)
        else:
            self.childerr = None