__init__.py 文件源码

def ioctl_fn_ptr_wr(request, datatype, return_python=None):
    """ Create a helper function for invoking a ioctl() read & write call.

    This function creates a helper function for a ioctl() operation that both reads and writes data.
    Typically the case is a ioctl() operation that receives a pointer to data, performs an operation and updates the data at the pointer.
    E.g. if you have a ioctl() call like::

      int timeout = 45;
      ioctl(fd, WDIOF_SETTIMEOUT, &timeout);
      printf("Actual timeout: %d\n", timeout);

    :param request: The ioctl request to call.
    :param datatype: The data type of the data to be passed to the ioctl() call.
    :param return_python: Whether we should attempt to convert the return data to a Python value. Defaults to True for fundamental ctypes data types.
    :return: A function for invoking the specified ioctl().

    :Example:
      ::

          import ctypes
          import os
          import ioctl
          WDIOF_SETTIMEOUT = 0x0080
          wdiof_settimeout = ioctl.ioctl_fn_ptr_wr(WDIOF_SETTIMEOUT, ctypes.c_int)
          fd = os.open('/dev/watchdog', os.O_RDONLY)
          actual_timeout = wdiof_settimeout(fd, 60)
    """

    check_request(request)
    check_ctypes_datatype(datatype)
    if return_python is not None and not isinstance(return_python, bool):
        raise TypeError('return_python must be None or a boolean, but was {}'.format(return_python.__class__.__name__))

    if return_python is None:
        return_python = issubclass(datatype, ctypes._SimpleCData)

    def fn(fd, value):
        check_fd(fd)
        value = datatype(value)
        ioctl(fd, request, ctypes.byref(value))
        if return_python:
            return value.value
        else:
            return value
    return fn