DAQmxReadDigitalLines

int32 DAQmxReadDigitalLines (TaskHandle taskHandle, int32 numSampsPerChan, float64 timeout, bool32 fillMode, uInt8 readArray[], uInt32 arraySizeInBytes, int32 *sampsPerChanRead, int32 *numBytesPerSamp, bool32 *reserved);

Purpose

Reads multiple samples from each digital line in a task. Each line in a channel gets one byte per sample.

Parameters

Input
Name	Type	Description
taskHandle	TaskHandle	The task to read samples from.
numSampsPerChan	int32	The number of samples, per channel, to read. The default value of -1 (DAQmx_Val_Auto) reads all available samples. If readArray does not contain enough space, this function returns as many samples as fit in readArray. NI-DAQmx determines how many samples to read based on whether the task acquires samples continuously or acquires a finite number of samples. If the task acquires samples continuously and you set this parameter to -1, this function reads all the samples currently available in the buffer. If the task acquires a finite number of samples and you set this parameter to -1, the function waits for the task to acquire all requested samples, then reads those samples. If you set the Read All Available Data property to TRUE, the function reads the samples currently available in the buffer and does not wait for the task to acquire all requested samples.
timeout	float64	The amount of time, in seconds, to wait for the function to read the sample(s). The default value is 10.0 seconds. To specify an infinite wait, pass -1 (DAQmx_Val_WaitInfinitely). This function returns an error if the timeout elapses. A value of 0 indicates to try once to read the requested samples. If all the requested samples are read, the function is successful. Otherwise, the function returns a timeout error and returns the samples that were actually read.
fillMode	bool32	Specifies whether or not the samples are interleaved. Value Description DAQmx_Val_GroupByChannel Group by channel (non-interleaved) DAQmx_Val_GroupByScanNumber Group by scan number (interleaved)
arraySizeInBytes	uInt32	The size of the array, in samples, into which samples are read.
reserved	bool32 *	Reserved for future use. Pass NULL to this parameter.
Output
Name	Type	Description
readArray	uInt8 []	The array to read samples into. Each numBytesPerSamp corresponds to one sample per channel, with each element in that grouping corresponding to a line in that channel, up to the number of lines contained in the channel.
sampsPerChanRead	int32 *	The actual number of samples read from each channel.
numBytesPerSamp	int32 *	The number of elements in readArray that constitutes a sample per channel. For each sample per channel, numBytesPerSamp is the number of bytes that channel consists of.

Return Value

Name	Type	Description
status	int32	The error code returned by the function in the event of an error or warning. A value of 0 indicates success. A positive value indicates a warning. A negative value indicates an error.