Thread: unknown size of type 'void'

Hi, i'm fairly new to C programming and i'm using LabWINDOWS/CVI to compile a c program. the only difference between my program that compiles with no errors and this one is the version of LabWindows. My code is below and the error i get is 'unknown size of type 'void'' and 'Operands of = have illegal types 'void' and 'int''. i realize i probably need to typecast something specific here, but the solutions i have tried haven't done the trick. Any thoughts?

void acquire_dc_voltage( CAObjHandle TS_seqContextCVI, double which_voltage,
double *measured_value,
char reportText[1024], short *errorOccurred,
long *errorCode, char errorMsg[1024] )
{
ERRORINFO errorInfo;
switch( (int)which_voltage ) // DANGER...int cast may delete lower bits
{
case ECG_MUX_SEL_AVDD3V :
// set ADC mux to AVDD3V
*(pdaq_fpga_base_addr + OFFSET_ECG_MUX_SEL_REG) = ECG_MUX_SEL_AVDD3V;

Your code is not complete. Because of this I can't see the problem.

Please post the complete, properly FORMATTED code.

Adding to the above, pdaq_fpga_base_addr is clearly critical yet you don't show its declaration or initialisation. According to this thread it needs an initialisation function - assuming it refers to the same version.

sorry... my initialization is in another file. I've copied and pasted where it's initialized and i included the rest of the function. For lack of NDA purposes i can't post the entire code. Thanks for taking a look

Header file for initialization:

************************************************** ***************************
*
* DLL library global variables
*
************************************************** ****************************/
// in PDAQ_PCI_access.c

Code:

extern ViAddr pdaq_fpga_base_addr;

reflecting comment that it is used in PDAQ_PCI_access.c, here is the code snippet from there:
/************************************************** ***********************
* Local Global variables
************************************************** ************************/

Code:

unsigned long int pdaq_pci_bar2_size = 0x80000;
unsigned long int pdaq_pci_bar3_size = 0x100;
unsigned long int pdaq_pci_bar0_size = 0x100;
ViAddr pdaq_plx_base_addr;
ViAddr pdaq_fpga_base_addr;
ViAddr pdaq_cpld_base_addr;
ViSession defaultRM, PDAQ3_PLX_FPGA, PDAQ3_PLX_CPLD, PDAQ3_PLX_REGS, ACQ_PC;

The entire void function where it is used:


/************************************************** ***************************
*
* Name : acquire_dc_voltage()
*
* Description :
* Aquire DC voltage reading from ECG ADC and returns measured value
* to TestStand
*
* Inputs :
*
* Outputs :
*
************************************************** ***************************/

Code:

void acquire_dc_voltage( CAObjHandle TS_seqContextCVI, double which_voltage,
                         double *measured_value,
                         char reportText[1024], short *errorOccurred,
                         long *errorCode, char errorMsg[1024] )
{
  ERRORINFO errorInfo;
  switch( (int)which_voltage )   // DANGER...int cast may delete lower bits
  {
     case ECG_MUX_SEL_AVDD3V :
          // set ADC mux to AVDD3V
          *(pdaq_fpga_base_addr + OFFSET_ECG_MUX_SEL_REG) = ECG_MUX_SEL_AVDD3V;
          
          // start ADC conversion
          
          // wait for done...if stalled, report error and break
          
          // read value
          
          // add/subtract offset/gain value (AGND reading)
          
          break;
     default :
          *errorOccurred = TRUE;
          *errorCode = -1;
          sprintf( errorMsg, "ERROR: illegal DC voltage requested \n"
                             "voltage select number s/b 0 to 15, requested = %05d",
                             (int)which_voltage );
          sprintf( reportText, "ERROR: illegal DC voltage requested \n"
                             "voltage select number s/b 0 to 15, requested = %05d",
                             (int)which_voltage );
          return;
  }; // end switch( which_voltage )

I was able to solve this by typecasting the equation as unsigned long. See solution below:

Code:

void acquire_dc_voltage( CAObjHandle TS_seqContextCVI, double which_voltage,
                         double *measured_value,
                         char reportText[1024], short *errorOccurred,
                         long *errorCode, char errorMsg[1024] )
{
  ERRORINFO errorInfo;
  switch( (int)which_voltage )   // DANGER...int cast may delete lower bits
  {
     case ECG_MUX_SEL_AVDD3V :
          // set ADC mux to AVDD3V
          *(unsigned long*)((unsigned long)pdaq_fpga_base_addr + OFFSET_ECG_MUX_SEL_REG) = (unsigned long)ECG_MUX_SEL_AVDD3V;
          
          // start ADC conversion
          
          // wait for done...if stalled, report error and break
          
          // read value
          
          // add/subtract offset/gain value (AGND reading)
          
          break;
     default :
          *errorOccurred = TRUE;
          *errorCode = -1;
          sprintf( errorMsg, "ERROR: illegal DC voltage requested \n"
                             "voltage select number s/b 0 to 15, requested = %05d",
                             (int)which_voltage );
          sprintf( reportText, "ERROR: illegal DC voltage requested \n"
                             "voltage select number s/b 0 to 15, requested = %05d",
                             (int)which_voltage );
          return;
  }; // end switch( which_voltage )