query_io_deviceT_query_io_deviceQueryIoDeviceQueryIoDevicequery_io_device (算子)

名称

query_io_deviceT_query_io_deviceQueryIoDeviceQueryIoDevicequery_io_device — 查询指定输入/输出设备的通道信息。

签名

query_io_device( : : IODeviceHandle, IOChannelName, Query : Result)

描述

算子 query_io_devicequery_io_deviceQueryIoDeviceQueryIoDeviceQueryIoDevicequery_io_device returns information about transmission channels of a specified I/O device. The handle to the I/O device is passed to in IODeviceHandleIODeviceHandleIODeviceHandleIODeviceHandleIODeviceHandleiodevice_handle, whereas the channels are addressed by IOChannelNameIOChannelNameIOChannelNameIOChannelNameIOChannelNameiochannel_name. The desired information about the I/O channels is specified via QueryQueryQueryQueryqueryquery. A list of all supported channel names is usually returned when passing 'io_channel_name'"io_channel_name""io_channel_name""io_channel_name""io_channel_name""io_channel_name" to QueryQueryQueryQueryqueryquery while the input parameter IOChannelNameIOChannelNameIOChannelNameIOChannelNameIOChannelNameiochannel_name is ignored.

Please check the directory doc/html/reference/io for documentation about your specific I/O device interface, where all supported channel-specific parameters are listed.

执行信息

多线程类型：可重入（与非独占算子并行运行）。
多线程作用域：全局（可从任何线程调用）。
未采用并行化处理。

参数

IODeviceHandleIODeviceHandleIODeviceHandleIODeviceHandleIODeviceHandleiodevice_handle (输入控制) io_device → (handle)

Handle of the opened I/O device.

IOChannelNameIOChannelNameIOChannelNameIOChannelNameIOChannelNameiochannel_name (输入控制) string(-array) → (string)

Channel names to query.

QueryQueryQueryQueryqueryquery (输入控制) string-array → (string)

Name of the query.

默认值： 'param_name' "param_name" "param_name" "param_name" "param_name" "param_name"

值列表： 'io_channel_names'"io_channel_names""io_channel_names""io_channel_names""io_channel_names""io_channel_names", 'param_name'"param_name""param_name""param_name""param_name""param_name"

ResultResultResultResultresultresult (输出控制) string-array → (string / integer / real)

List of values (according to QueryQueryQueryQueryqueryquery).

示例（HDevelop）

* Select a suitable i/o device interface of name IOInterfaceName
query_io_interface (IOInterfaceName, 'io_device_names', DeviceNames)
open_io_device (IOInterfaceName, DeviceNames[0], [], [], IODeviceHandle)
query_io_device (IODeviceHandle, [], 'io_channel_names.digital_input', \
                 ChannelInputNames)
open_io_channel (IODeviceHandle, ChannelInputNames[0], [], [], \
                 IOChannelHandle)
read_io_channel (IOChannelHandle, Value, Status)

结果

如果参数有效，算子 query_io_devicequery_io_deviceQueryIoDeviceQueryIoDeviceQueryIoDevicequery_io_device 返回值 2 ( H_MSG_TRUE )。如有必要，则抛出异常。在这种情况下，可以设置扩展错误信息，并可进行查询通过算子 get_extended_error_infoget_extended_error_infoGetExtendedErrorInfoGetExtendedErrorInfoGetExtendedErrorInfoget_extended_error_info。

可能的后继

open_io_deviceopen_io_deviceOpenIoDeviceOpenIoDeviceOpenIoDeviceopen_io_device

模块

基础

算子