open_io_deviceT_open_io_deviceOpenIoDeviceOpenIoDeviceopen_io_device (算子)

名称

open_io_deviceT_open_io_deviceOpenIoDeviceOpenIoDeviceopen_io_device — 打开并配置输入/输出设备。

签名

描述

算子 open_io_deviceopen_io_deviceOpenIoDeviceOpenIoDeviceOpenIoDeviceopen_io_device opens and configures the chosen I/O device interface for the specific device. The device interface is specified by the base name of the underlying library and passed to IOInterfaceNameIOInterfaceNameIOInterfaceNameIOInterfaceNameIOInterfaceNameiointerface_name. The interface library will be loaded dynamically when configuring the first specific device for this device interface. The specific device itself is addressed by a name passed to IODeviceNameIODeviceNameIODeviceNameIODeviceNameIODeviceNameiodevice_name. Available names can be queried by query_io_interfacequery_io_interfaceQueryIoInterfaceQueryIoInterfaceQueryIoInterfacequery_io_interface。The device can be configured by the parameters GenParamNameGenParamNameGenParamNameGenParamNamegenParamNamegen_param_name and GenParamValueGenParamValueGenParamValueGenParamValuegenParamValuegen_param_value. A reference to the device instance is returned in IODeviceHandleIODeviceHandleIODeviceHandleIODeviceHandleIODeviceHandleiodevice_handle. If the instance of the device is not needed any more, it should be released and closed via the operator close_io_deviceclose_io_deviceCloseIoDeviceCloseIoDeviceCloseIoDeviceclose_io_device。

Having opened a specific device, a transmission channel can be opened by calling open_io_channelopen_io_channelOpenIoChannelOpenIoChannelOpenIoChannelopen_io_channel。Values on the I/O channel can be read and written by the operators read_io_channelread_io_channelReadIoChannelReadIoChannelReadIoChannelread_io_channel and write_io_channelwrite_io_channelWriteIoChannelWriteIoChannelWriteIoChannelwrite_io_channel on an opened transmission channel, afterwards.

An opened device instance can be reconfigured by using the operators set_io_device_paramset_io_device_paramSetIoDeviceParamSetIoDeviceParamSetIoDeviceParamset_io_device_param and get_io_device_paramget_io_device_paramGetIoDeviceParamGetIoDeviceParamGetIoDeviceParamget_io_device_param。

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

注意

On Windows Systems, error dialog boxes from the operating system can occur when dependency modules of the interface are not found, e.g., the according SDK was not installed. The occurrence of the error boxes can be controlled by setting Windows' Error Mode. Please refer to the description of SetErrorMode within the Windows MSDN documentation.

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。

此算子返回一个句柄。请注意，即使该句柄被用作特定算子的输入参数，这些算子仍可能改变此句柄类型的实例状态。

参数

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 open_io_deviceopen_io_deviceOpenIoDeviceOpenIoDeviceOpenIoDeviceopen_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。

可能的前趋

query_io_interfacequery_io_interfaceQueryIoInterfaceQueryIoInterfaceQueryIoInterfacequery_io_interface

可能的后继

set_io_device_paramset_io_device_paramSetIoDeviceParamSetIoDeviceParamSetIoDeviceParamset_io_device_param, get_io_device_paramget_io_device_paramGetIoDeviceParamGetIoDeviceParamGetIoDeviceParamget_io_device_param, open_io_channelopen_io_channelOpenIoChannelOpenIoChannelOpenIoChannelopen_io_channel

模块

基础