open_io_channelT_open_io_channelOpenIoChannelOpenIoChannel (Operator)

Name

open_io_channelT_open_io_channelOpenIoChannelOpenIoChannel — Open and configure I/O channels.

Signature

Description

The operator open_io_channelopen_io_channelOpenIoChannelOpenIoChannelOpenIoChannel opens and configures transmission channels of an opened I/O device instance. The device instance must have been opened by open_io_deviceopen_io_deviceOpenIoDeviceOpenIoDeviceOpenIoDevice before and is passed to IODeviceHandleIODeviceHandleIODeviceHandleIODeviceHandleIODeviceHandle. The transmission channels themselves are addressed by their names passed to IOChannelNameIOChannelNameIOChannelNameIOChannelNameIOChannelName. Available names can be queried using query_io_devicequery_io_deviceQueryIoDeviceQueryIoDeviceQueryIoDevice with query parameter 'io_channel_name'"io_channel_name""io_channel_name""io_channel_name""io_channel_name". The channels can be configured by the parameters GenParamNameGenParamNameGenParamNameGenParamNamegenParamName and GenParamValueGenParamValueGenParamValueGenParamValuegenParamValue. A reference to each transmission channel is returned in IOChannelHandleIOChannelHandleIOChannelHandleIOChannelHandleIOChannelHandle. If the instance of the channel is not needed any more, it should be released and closed via the operator close_io_channelclose_io_channelCloseIoChannelCloseIoChannelCloseIoChannel. Besides, it will be closed automatically when closing the associated device instance by close_io_deviceclose_io_deviceCloseIoDeviceCloseIoDeviceCloseIoDevice.

Having opened a transmission channel, values can be read and written by the operators read_io_channelread_io_channelReadIoChannelReadIoChannelReadIoChannel and write_io_channelwrite_io_channelWriteIoChannelWriteIoChannelWriteIoChannel on the channel.

An opened channel can be reconfigured by using the operators set_io_channel_paramset_io_channel_paramSetIoChannelParamSetIoChannelParamSetIoChannelParam and get_io_channel_paramget_io_channel_paramGetIoChannelParamGetIoChannelParamGetIoChannelParam.

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

Execution Information

• Multithreading type: reentrant (runs in parallel with non-exclusive operators).
• Multithreading scope: global (may be called from any thread).
• Processed without parallelization.

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.

Parameters

Example (HDevelop)

query_io_device (IODeviceHandle, [], 'io_channel_names.digital_output', ChannelOutputNames)
open_io_channel (IODeviceHandle, ChannelOutputNames[0], [], [], IOChannelHandle)
write_io_channel (IOChannelHandle, 1, Status)

Result

If the parameters are valid, the operator open_io_channelopen_io_channelOpenIoChannelOpenIoChannelOpenIoChannel returns the value 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 the operator get_extended_error_infoget_extended_error_infoGetExtendedErrorInfoGetExtendedErrorInfoGetExtendedErrorInfo.

Possible Predecessors

open_io_deviceopen_io_deviceOpenIoDeviceOpenIoDeviceOpenIoDevice, query_io_devicequery_io_deviceQueryIoDeviceQueryIoDeviceQueryIoDevice

Possible Successors

set_io_channel_paramset_io_channel_paramSetIoChannelParamSetIoChannelParamSetIoChannelParam, read_io_channelread_io_channelReadIoChannelReadIoChannelReadIoChannel, write_io_channelwrite_io_channelWriteIoChannelWriteIoChannelWriteIoChannel

Module

Foundation