Method write

Lib/_pyio.py:1732–1744

Write bytes b to file, return number written. Only makes one system call, so not all of the data may be written. The number of bytes actually written is returned. In non-blocking mode, returns None if the write would block.

(self, b)

            return None

    def write(self, b):
        """Write bytes b to file, return number written.

        Only makes one system call, so not all of the data may be written.
        The number of bytes actually written is returned.  In non-blocking mode,
        returns None if the write would block.
        """
        self._checkClosed()
        self._checkWritable()
        try:
            return os.write(self._fd, b)
        except BlockingIOError:
            return None

    def seek(self, pos, whence=SEEK_SET):
        """Move to new file position.