capture.py 文件源码

def __init__(self, targetfd, tmpfile=None, now=True, patchsys=False):
        """ save targetfd descriptor, and open a new
            temporary file there.  If no tmpfile is
            specified a tempfile.Tempfile() will be opened
            in text mode.
        """
        self.targetfd = targetfd
        if tmpfile is None and targetfd != 0:
            f = tempfile.TemporaryFile('wb+')
            tmpfile = dupfile(f, encoding="UTF-8")
            f.close()
        self.tmpfile = tmpfile
        self._savefd = os.dup(self.targetfd)
        if patchsys:
            self._oldsys = getattr(sys, patchsysdict[targetfd])
        if now:
            self.start()