prog_class.py 文件源码

def _check_stream(self):
        """Determines which output stream (stdout, stderr, or custom) to use"""
        if self.stream:
            try:
                if self.stream == 1 and os.isatty(sys.stdout.fileno()):
                    self._stream_out = sys.stdout.write
                    self._stream_flush = sys.stdout.flush
                elif self.stream == 2 and os.isatty(sys.stderr.fileno()):
                    self._stream_out = sys.stderr.write
                    self._stream_flush = sys.stderr.flush

            # a fix for IPython notebook "IOStream has no fileno."
            except UnsupportedOperation:
                if self.stream == 1:
                    self._stream_out = sys.stdout.write
                    self._stream_flush = sys.stdout.flush
                elif self.stream == 2:
                    self._stream_out = sys.stderr.write
                    self._stream_flush = sys.stderr.flush
            else:
                if self.stream is not None and hasattr(self.stream, 'write'):
                    self._stream_out = self.stream.write
                    self._stream_flush = self.stream.flush
        else:
            print('Warning: No valid output stream.')