How To Solve these errors: error: "initializer element is not constant (void (*)(void))((uint32_t)&__STACK_TOP)" and "error: (near initialization for 'g_pfnVectors[0]')"

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Alberto Prud'homme on 20 Apr 2016

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https://se.mathworks.com/matlabcentral/answers/280135-how-to-solve-these-errors-error-initializer-element-is-not-constant-void-void-uint32_t-_

Answered: Venkatachala Sarma on 6 May 2016

Hello;

I made a modification in a serial transmitt program in C and it works very well when I send to my Tiva C target from TI, but this program will be a part of a simulink program, so I need to insert the C code with a function block to simulink.

When I debug the code in Simulink I receive these errors:

Building with 'MinGW64 Compiler (C)'. 
C:\Users\Alberto\Desktop\ENVIOS~1\startup_ccs.c:43:20: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast] 
   (void (*)(void))((uint32_t)&__STACK_TOP), 
                    ^ 
C:\Users\Alberto\Desktop\ENVIOS~1\startup_ccs.c:43:3: error: initializer element is not constant 
   (void (*)(void))((uint32_t)&__STACK_TOP), 
   ^ 
C:\Users\Alberto\Desktop\ENVIOS~1\startup_ccs.c:43:3: error: (near initialization for 'g_pfnVectors[0]') 
gmake: *** [startup_ccs.obj] Error -1

I don't understan the problem, because the code in C directly installed in the target works fine, but I was searching for days and I can't find the problem.

This is the C code:

#include <stdint.h>
#include <stdio.h>
#include <stdbool.h>
#include <math.h>
#include "hw_ints.h"
#include "hw_memmap.h"
#include "debug.h"
#include "fpu.h"
#include "gpio.h"
#include "interrupt.h"
#include "pin_map.h"
#include "rom.h"
#include "sysctl.h"
#include "uart.h"
char car[2000];
double u;
void UARTSend2(const uint8_t *pui8Buffer, uint32_t ui32Count);
//*****************************************************************************
// Send a string to the UART.
void UARTSend2(const uint8_t *pui8Buffer, uint32_t ui32Count)
{
      ROM_FPUEnable(); // Enable lazy stacking for interrupt handlers.  This allows floating-point
      ROM_FPULazyStackingEnable(); // instructions to be used within interrupt handlers, but at the expense of extra stack usage.
      ROM_SysCtlClockSet(SYSCTL_SYSDIV_1 | SYSCTL_USE_OSC | SYSCTL_OSC_MAIN | SYSCTL_XTAL_16MHZ); // Set the clocking to run directly from the crystal.
      ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOF);    // Enable the GPIO port that is used for the on-board LED.
      ROM_GPIOPinTypeGPIOOutput(GPIO_PORTF_BASE, GPIO_PIN_2); // Enable the GPIO pins for the LED (PF2).
      ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_UART0); // Enable the peripherals used by this example.
      ROM_SysCtlPeripheralEnable(SYSCTL_PERIPH_GPIOA);
      ROM_IntMasterEnable(); // Enable processor interrupts.
      GPIOPinConfigure(GPIO_PA0_U0RX); // Set GPIO A0 and A1 as UART pins.
      GPIOPinConfigure(GPIO_PA1_U0TX);
      ROM_GPIOPinTypeUART(GPIO_PORTA_BASE, GPIO_PIN_0 | GPIO_PIN_1);
      ROM_UARTConfigSetExpClk(UART0_BASE, ROM_SysCtlClockGet(), 115200,  // Configure the UART for 115,200, 8-N-1 operation.
                              (UART_CONFIG_WLEN_8 | UART_CONFIG_STOP_ONE |
                               UART_CONFIG_PAR_NONE));
      while(ui32Count--) // Loop while there are more characters to send.
      {
          ROM_UARTCharPutNonBlocking(UART0_BASE, *pui8Buffer++);  // Write the next character to the UART.
      }
    }
  //*****************************************************************************
  // This example demonstrates how to send a string of data to the UART.
  int
  main(double u)
  {
        u=1234;
        int cont=(log10(u))+6;
        sprintf (car,"%.2f\r\n",u);
        UARTSend2((uint8_t *) car,cont); // Prompt for text to be entered.
}

And this is the block of the code where Simulink notify the error in the file startup_ccs.c:

//*****************************************************************************
//
// External declaration for the interrupt handler used by the application.
//
//*****************************************************************************
//extern void UARTIntHandler(void);
//*****************************************************************************
//
// The vector table.  Note that the proper constructs must be placed on this to
// ensure that it ends up at physical address 0x0000.0000 or at the start of
// the program if located at a start address other than 0.
//
//*****************************************************************************
#pragma DATA_SECTION(g_pfnVectors, ".intvecs")
void (* const g_pfnVectors[])(void) =
{
  (void (*)(void))((uint32_t)&__STACK_TOP),
                                            // The initial stack pointer
    ResetISR,                               // The reset handler
    NmiSR,                                  // The NMI handler
    FaultISR,                               // The hard fault handler
    IntDefaultHandler,                      // The MPU fault handler
    IntDefaultHandler,                      // The bus fault handler
    IntDefaultHandler,                      // The usage fault handler
    0,                                      // Reserved
    0,                                      // Reserved