Programming NI-DAQmx in Visual C++ .NET 2003

[David_Lin]

Hi,

I have problems in using NI-DAQmx in VC+.NET 2003. I have read the KB article https://www.ni.com/en/support/documentation/supplemental/18/archived--programming-traditional-ni-daq... and I followed the steps in the last part for NI-DAQmx. However, when I compiled my project, this error still came:

error LNK2019: unresolved external symbol _DAQmxCreateTask@8 referenced in function "public: long __thiscall CDAQmxfunc::Configure_AcqIntClkAnlgStart(char const * const,double,double,unsigned long,double,unsigned long *,unsigned long *)" (?Configure_AcqIntClkAnlgStart@CDAQmxfunc@@QAEJQBDNNKNPAK1@Z)

which means the lib files still couldn't be found. After I added the NIDAQmx.lib in my project, this problem is solved.  Did I make the right move? Also, when I referred to the DAQmx ANSI C samples for NI-DAQmx, I saw only this header file NIDAQmx.h is included. Is it the same in VC++.NET?

Thank you very much.

David

[Hal_L]

Hi David,

You did the correct thing by adding the NIDAQmx.lib file to your project. Also, the NIDAQmx.h file is the same.

Regards,
Hal L.

[slastuka]

I have a similar problem in VS 2008.  I can compile the example code (VC_ContFreq_IntClk_SCXI1126) no problem from Visual Studio 2008.

However, when I create my own project in visual studio with the same #includes i get the same errors:  

Compiling...

DTRTestNov2010.c

Linking...

DTRTestNov2010.obj: error LNK2019: unresoloved external symbol _DAQmxClearTask@4 reference in function _main

DTRTestNov2010.obj: error LNK2019: unresoloved external symbol _DAQmxStopTask@4 reference in function _main

and so on... for all other function calls I made.  

i am not a pro at c-programming.  Am I supposed to setup a 'linker' somehow? 

Thanks!

Sean

Here is my c-code (which operates in matlab typically, but I think is spawning a memory leak, so i'd like to test it in native C)

#include <stdio.h>

#include <NIDAQmx.h>

#define DAQmxErrChk(functionCall) if( DAQmxFailed(error=(functionCall)) ) goto Error; else

int main(void)

{

int32       error=0;

TaskHandle  masterTaskHandle=0;

TaskHandle  slaveTaskHandle=0;

int32       read;

int32 fs=30000;

int32 samplesPerLoop=30000;

int32 channels=4;

int32 arrayLength;

float64     data[30000];

char        errBuff[2048]={'\0'};

arrayLength  = samplesPerLoop * channels;

/*********************************************/

// DAQmx Configure Code

/*********************************************/

DAQmxErrChk (DAQmxCreateTask("",&masterTaskHandle));

DAQmxErrChk (DAQmxCreateTask("",&slaveTaskHandle));

DAQmxErrChk (DAQmxCreateAIVoltageChan(masterTaskHandle,"Dev1/ai0:3","",DAQmx_Val_Cfg_Default,-10.0,10.0,DAQmx_Val_Volts,NULL));

DAQmxErrChk (DAQmxCreateAIVoltageChan(slaveTaskHandle,"Dev1/ai0:3","",DAQmx_Val_Cfg_Default,-10.0,10.0,DAQmx_Val_Volts,NULL));

DAQmxErrChk (DAQmxCfgSampClkTiming(masterTaskHandle,"",fs,DAQmx_Val_Rising,DAQmx_Val_FiniteSamps,samplesPerLoop));

DAQmxErrChk (DAQmxCfgSampClkTiming(slaveTaskHandle,"",fs,DAQmx_Val_Rising,DAQmx_Val_FiniteSamps,samplesPerLoop));

DAQmxErrChk (DAQmxCfgInputBuffer(masterTaskHandle,samplesPerLoop*2));

DAQmxErrChk (DAQmxCfgInputBuffer(slaveTaskHandle,samplesPerLoop*2));

DAQmxErrChk (DAQmxExportSignal(masterTaskHandle,DAQmx_Val_StartTrigger,"RTSI0"));

DAQmxErrChk (DAQmxCfgDigEdgeStartTrig(slaveTaskHandle,"RTSI0",DAQmx_Val_Rising));

DAQmxErrChk (DAQmxSetExportedSampClkTimebaseOutputTerm(masterTaskHandle,"/Dev1/RTSI8"));

DAQmxErrChk (DAQmxSetSampClkTimebaseSrc(slaveTaskHandle,"RTSI8"));

DAQmxErrChk (DAQmxSetExportedSyncPulseEventOutputTerm(masterTaskHandle,"/Dev1/RTSI9"));

DAQmxErrChk (DAQmxSetSyncPulseSrc(slaveTaskHandle,"RTSI9"));

/*********************************************/

// DAQmx Start Code

/*********************************************/

DAQmxErrChk (DAQmxStartTask(slaveTaskHandle));

DAQmxErrChk (DAQmxStartTask(masterTaskHandle));

/*********************************************/

// DAQmx Read Code

/*********************************************/

DAQmxErrChk (DAQmxReadAnalogF64(masterTaskHandle,samplesPerLoop,5.0,DAQmx_Val_GroupByChannel,data,samplesPerLoop,&read,NULL));

DAQmxErrChk (DAQmxReadAnalogF64(slaveTaskHandle,samplesPerLoop,5.0,DAQmx_Val_GroupByChannel,data,samplesPerLoop,&read,NULL));

printf("Acquired %d points\n",read);

Error:

if( DAQmxFailed(error) )

DAQmxGetExtendedErrorInfo(errBuff,2048);

if( masterTaskHandle!=0 )  {

/*********************************************/

// DAQmx Stop Code

/*********************************************/

DAQmxStopTask(slaveTaskHandle);

DAQmxStopTask(masterTaskHandle);

DAQmxClearTask(slaveTaskHandle);

DAQmxClearTask(masterTaskHandle);

}

if( DAQmxFailed(error) )

printf("DAQmx Error: %s\n",errBuff);

printf("End of program, press Enter key to quit\n");

getchar();

return 0;

}

[Brad_K]

Hi Sean,

Yes, you must tell the linker where nidaqmx.lib is located. Here are a couple of KBs explaining how to do this:

When Compiling a DAQmx ANSI C Example in Visual C++ I Receive Link Errors

Location of ANSI C NI-DAQmx Shipping Examples and DAQmx Library File for Windows

Brad