open_io_deviceT_open_io_deviceOpenIoDeviceOpenIoDeviceopen_io_device (算子名称)

名称

open_io_deviceT_open_io_deviceOpenIoDeviceOpenIoDeviceopen_io_device — Open and configure an I/O device.

参数签名

描述

该算子 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 该算子 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 该算子s 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 该算子s 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.

运行信息

• 多线程类型:可重入(与非独占操作符并行运行)。
• 多线程作用域:全局(可以从任何线程调用)。
• 未经并行化处理。

This operator returns a handle. Note that the state of an instance of this handle type may be changed by specific operators even though the handle is used as an input parameter by those operators.

参数表

例程 (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

如果参数均有效，算子 open_io_deviceopen_io_deviceOpenIoDeviceOpenIoDeviceOpenIoDeviceopen_io_device 返回值 2 ( H_MSG_TRUE) . If necessary an exception is raised. In this case, an extended error information may be set and can be queried with 该算子 get_extended_error_infoget_extended_error_infoGetExtendedErrorInfoGetExtendedErrorInfoGetExtendedErrorInfoget_extended_error_info.

可能的前置算子

query_io_interfacequery_io_interfaceQueryIoInterfaceQueryIoInterfaceQueryIoInterfacequery_io_interface

可能的后置算子

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

Foundation

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