I’m developing a driver for a NIDAQ device (PXIe-6738) and have run into an issue. The program reads data from a file and then writes those data to two output channels (I and Q).
My analog write output function is
DAQmxErrChk (DAQmxWriteAnalogF64(taskHandle1, samples_per_channel,0,10.0,DAQmx_Val_GroupByChannel,*I_chan_buffer,NULL,NULL));
The issue is with the argument “*I_chan_buffer”. When I build my code, I am greeted with an error telling me that the type of *I_chan_buffer, which is int16, is not compatible with the argument type, which is an array of floats: float64[].
But I do not understand why I am getting this error. I took the following steps to initialize and populate “I_chan_buffer”
std::int16_t* I_chan_buffer = (std::int16_t*) calloc(ulCount / 2, sizeof(float));
std::int16_t* Q_chan_buffer = (std::int16_t*) calloc(ulCount / 2, sizeof(float));
ulCount = filesize/(sizeof(std::int16_t)); // This is equal to the total number of data points for both I and Q
for (i=0; i<ulCount;i++)
{
fread(&TempBuffer, sizeof(std::int16_t), 1, fp);
if (i%2 == 0){
I_chan_buffer[i] = (float)(TempBuffer - 0x8000);
}
else{
Q_chan_buffer[i] = (float)(TempBuffer - 0x8000);
}
}
fclose(fp);
based on this assignment of a float to each element of the I and Q channel, I reason that the dereferencing of the associated array pointers should be of type float. That is,
*I_chan_buffer should resolve to an array of floats. I have also attempted passing I_chan_buffer and Q_chan_buffer directly but I get the same error telling me that the input argument is of type int16 which is incompatible with float64[].
Is anyone aware of what I may be doing wrong here?
Thanks
