Thread: Function Call

Hello,

Below is a sample data acquisition code. It compiles fine. I would like to make it a function and call it within another main function (program). So I did this:

int main(void) ---> void DAQ()

It gives me bunch of errors. Can anyone please tell me where my mistake is?

Cheers

Code:

int main(void)
{
	int32       error=0;
	TaskHandle  taskHandle=0;
	int32       read;
	float64     data[1000];
	char        errBuff[2048]={'\0'};


	/*********************************************/
	// DAQmx Configure Code
	/*********************************************/
	DAQmxErrChk (DAQmxCreateTask("",&taskHandle));
	DAQmxErrChk (DAQmxCreateAIVoltageChan(taskHandle,"Dev1/ai0","",DAQmx_Val_Cfg_Default,-10.0,10.0,DAQmx_Val_Volts,NULL));
	DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandle,"/Dev1/PFI7",1000.0,DAQmx_Val_Rising,DAQmx_Val_FiniteSamps,1000));


	/*********************************************/
	// DAQmx Start Code
	/*********************************************/
	DAQmxErrChk (DAQmxStartTask(taskHandle));


	/*********************************************/
	// DAQmx Read Code
	/*********************************************/
	DAQmxErrChk (DAQmxReadAnalogF64(taskHandle,-1,10.0,DAQmx_Val_GroupByChannel,data,1000,&read,NULL));


	if( read>0 )
		printf("Acquired %d samples\n",(int)read);


Error:
	if( DAQmxFailed(error) )
		DAQmxGetExtendedErrorInfo(errBuff,2048);
	if( taskHandle!=0 ) {
		/*********************************************/
		// DAQmx Stop Code
		/*********************************************/
		DAQmxStopTask(taskHandle);
		DAQmxClearTask(taskHandle);
	}
	if( DAQmxFailed(error) )
		printf("DAQmx Error: %s\n",errBuff);
	printf("End of program, press Enter key to quit\n");
	getchar();
	return 0;
}

The main function is quite long, therefore I just pasted the function here. Even though you dont call a function in the main function, it still should compile fine. I am using gcc compiler on windows. My errors are as follows:

-------------------------------------------------------------------------------------------------
Main2.c:320:2: error: unknown type name 'int32'
int32 error=0;
^
Main2.c:321:2: error: unknown type name 'TaskHandle'
TaskHandle taskHandle=0;
^
Main2.c:322:2: error: unknown type name 'int32'
int32 read;
^
Main2.c:323:2: error: unknown type name 'float64'
float64 data[1000];
^
Main2.c:329:2: warning: implicit declaration of function 'DAQmxErrChk' [-Wimplicit-function-declaration]
DAQmxErrChk (DAQmxCreateTask("",&taskHandle));
^
Main2.c:329:15: warning: implicit declaration of function 'DAQmxCreateTask' [-Wimplicit-function-declaration]
DAQmxErrChk (DAQmxCreateTask("",&taskHandle));
^
Main2.c:330:15: warning: implicit declaration of function 'DAQmxCreateAIVoltageChan' [-Wimplicit-function-declaration]
DAQmxErrChk (DAQmxCreateAIVoltageChan(taskHandle,"Dev1/ai0","",DAQmx_Val_Cfg_Default,-10.0,10.0,DAQmx_Val_Volts,NULL));
^
Main2.c:330:65: error: 'DAQmx_Val_Cfg_Default' undeclared (first use in this function)
DAQmxErrChk (DAQmxCreateAIVoltageChan(taskHandle,"Dev1/ai0","",DAQmx_Val_Cfg_Default,-10.0,10.0,DAQmx_Val_Volts,NULL));
^
Main2.c:330:65: note: each undeclared identifier is reported only once for each function it appears in
Main2.c:330:98: error: 'DAQmx_Val_Volts' undeclared (first use in this function)
DAQmxErrChk (DAQmxCreateAIVoltageChan(taskHandle,"Dev1/ai0","",DAQmx_Val_Cfg_Default,-10.0,10.0,DAQmx_Val_Volts,NULL));
^
Main2.c:331:15: warning: implicit declaration of function 'DAQmxCfgSampClkTiming' [-Wimplicit-function-declaration]
DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandle,"",10000.0,DAQmx _Val_Rising,DAQmx_Val_FiniteSamps,1000));
^
Main2.c:331:59: error: 'DAQmx_Val_Rising' undeclared (first use in this function)
DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandle,"",10000.0,DAQmx _Val_Rising,DAQmx_Val_FiniteSamps,1000));
^
Main2.c:331:76: error: 'DAQmx_Val_FiniteSamps' undeclared (first use in this function)
DAQmxErrChk (DAQmxCfgSampClkTiming(taskHandle,"",10000.0,DAQmx _Val_Rising,DAQmx_Val_FiniteSamps,1000));
^
Main2.c:332:15: warning: implicit declaration of function 'DAQmxCfgAnlgEdgeStartTrig' [-Wimplicit-function-declaration]
DAQmxErrChk (DAQmxCfgAnlgEdgeStartTrig(taskHandle,"APFI0",DAQm x_Val_Rising,1.0));
^
Main2.c:333:15: warning: implicit declaration of function 'DAQmxSetAnlgEdgeStartTrigHyst' [-Wimplicit-function-declaration]
DAQmxErrChk (DAQmxSetAnlgEdgeStartTrigHyst(taskHandle, 1.0));
^
Main2.c:338:15: warning: implicit declaration of function 'DAQmxStartTask' [-Wimplicit-function-declaration]
DAQmxErrChk (DAQmxStartTask(taskHandle));
^
Main2.c:343:15: warning: implicit declaration of function 'DAQmxReadAnalogF64' [-Wimplicit-function-declaration]
DAQmxErrChk (DAQmxReadAnalogF64(taskHandle,-1,10.0,DAQmx_Val_GroupByChannel,data,1000,&read,NU LL));
^
Main2.c:343:53: error: 'DAQmx_Val_GroupByChannel' undeclared (first use in this function)
DAQmxErrChk (DAQmxReadAnalogF64(taskHandle,-1,10.0,DAQmx_Val_GroupByChannel,data,1000,&read,NU LL));
^
Main2.c:349:6: warning: implicit declaration of function 'DAQmxFailed' [-Wimplicit-function-declaration]
if( DAQmxFailed(error) )
^
Main2.c:350:3: warning: implicit declaration of function 'DAQmxGetExtendedErrorInfo' [-Wimplicit-function-declaration]
DAQmxGetExtendedErrorInfo(errBuff,2048);
^
Main2.c:355:3: warning: implicit declaration of function 'DAQmxStopTask' [-Wimplicit-function-declaration]
DAQmxStopTask(taskHandle);
^
Main2.c:356:3: warning: implicit declaration of function 'DAQmxClearTask' [-Wimplicit-function-declaration]
DAQmxClearTask(taskHandle);
^
Main2.c:362:9: warning: 'return' with a value, in function returning void
return 0;
^
---------------------------------------------------------------------------------------------------------------------------------------------------

Ohh thanks, you were right, I was missing the header file, forgot to add it. My errors reduced to:

--------------------------------------------------------------------------------------------------------------------------------------
Main2.c: In function 'NIDAQ':
Main2.c:330:2: warning: implicit declaration of function 'DAQmxErrChk' [-Wimplicit-function-declaration]
DAQmxErrChk (DAQmxCreateTask("",&taskHandle));
^
Main2.c:361:9: warning: 'return' with a value, in function returning void
return 0;
^
C:\Users\cyln~1\AppData\Local\Temp\cciX7oIt.o:Main 2.c.text+0x1231): undefined reference to `DAQmxErrChk'
C:\Users\cyln~1\AppData\Local\Temp\cciX7oIt.o:Main 2.c.text+0x1283): undefined reference to `DAQmxErrChk'
C:\Users\cyln~1\AppData\Local\Temp\cciX7oIt.o:Main 2.c.text+0x12cb): undefined reference to `DAQmxErrChk'
C:\Users\cyln~1\AppData\Local\Temp\cciX7oIt.o:Main 2.c.text+0x12e1): undefined reference to `DAQmxErrChk'
C:\Users\cyln~1\AppData\Local\Temp\cciX7oIt.o:Main 2.c.text+0x1332): undefined reference to `DAQmxErrChk'
collect2.exe: error: ld returned 1 exit status
-------------------------------------------------------------------------------------------------------------------------------------------------------------

You're missing this after the includes:

Code:

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

From Using NI-DAQmx in Text Based Programming Environments

Right, that was my second bug. Now I only get one error:

---------------------------------------------------------------------------------------------------------------------------
Main2.c: In function 'NIDAQ':
Main2.c:362:9: warning: 'return' with a value, in function returning void
return 0;
^
---------------------------------------------------------------------------------------------------------------------------

The issue is, main function calls a dozen of other funtions and most of them have void type. I cannot return 0 in the main function.

woww, thank you so much, it worked!