Thread: Function Pointer help

Hi im trying to make a function that returns a function pointer. ´
It would work like this, when the first function is called from my main loop, the next function it calls will be the second function.

It will remind a little bit about a state pattern, with the states changing inside the functions, and the main loop not knowing what state it is.

It looks like this:

Code:

typedef void * (*fptr)(char *, char *, signed char );  


void *InitCalibration(char * upperLcdTxt, char *lowerLcdTxt, signed char  Button);
void *Step2Calibration(char * upperLcdTxt, char *lowerLcdTxt, signed char  Button);


void *Step2Calibration(char * upperLcdTxt, char *lowerLcdTxt, signed char  Button)
{     
   fptr fp = InitCalibration;     
   
   char* temp = "Calibrationsmode";
   char* temp2 = "Press CAL 90 KG" ;              
   
   strcpy(upperLcdTxt, temp);
   strcpy(lowerLcdTxt, temp2);
   
   return &fp;

}

void *InitCalibration(char * upperLcdTxt, char *lowerLcdTxt, signed char  Button)
{
   fptr fp = Step2Calibration;                               
   char* temp = "Calibrationsmode";
   char* temp2 = "Press CAL 0 KG" ;              
   
   strcpy(upperLcdTxt, temp);
   strcpy(lowerLcdTxt, temp2);
   
   return &fp;
}

Then i would attempt to cast the return value to the right function pointer from my main.

main looks like this:

Code:

  fptr fp = &InitCalibration;
  while (1)
  {      
    delay_ms(2000);
       
    keyBoardVal = keyboard();
    fp = (fptr) fp(convert, convert2, keyBoardVal);
         
           
  };

so every time fp function pointer calls a function its a different one, but it doesnt work, what could be wrong.

The adress changing in the main loop doesnt work, fp points nowhere, and i might have misunderstood all this function pointer stuff, so please help me correct my errors

> void *InitCalibration(char * upperLcdTxt, char *lowerLcdTxt, signed char Button);
Having declared the typedef for the function pointer, you may as well use it

fptr InitCalibration(char * upperLcdTxt, char *lowerLcdTxt, signed char Button);

Fisherrandom: I wanted to do this, because in the end it would be build up like a state pattern. The individual functions would change the state of the program by the users keyboard input.

I made it work with a global variable that got assigned the new function it should point to, and the function return value was removed.

Thx for the help, :-)

Why did you need to use a global to achieve that?