Help needed with ISR function ptr compiler error

David Aldrich92784

I am working on a Keystone II DSP project. I am having difficulty fixing a compiler error related to a function pointer for an ISR.

The following code is defined in a .cpp file:

extern void System_registerIsr(uint32 sysEvent, uint32 hostEvent, void (*fxn)(UArg));

// Table to define the interrupt sources
typedef struct
{
    EIntMap intCoreMap;
    uint32 systemInterrupt;
    uint32 hostInterrupt;
    uint32 hwInterrupt;
    void (*isrHandler)(UArg arg);
}Ctrl_IsrCfgTable;

Ctrl_IsrCfgTable IsrCfgTable[ISR_NUM_ENTRIES] =
{
  {INT_COREA, 158, 68, 4, &Isr_A},
  {INT_COREA, 300, 69, 5, &Isr_B},
<snip>
};

void myFunc()

    System_registerIsr( IsrCfgTable[idx].systemInterrupt,
                                    IsrCfgTable[idx].hostInterrupt,
                                    IsrCfgTable[idx].isrHandler );

The call to System_registerIsr() yields error:

error #169: argument of type "void (*)(UArg) C" is incompatible with parameter of type "void (*)(UArg)"

System_registerIsr() is declared in another .cpp file.

Why am I getting this error?

Best regards

David

over 12 years ago

0 Archaeologist over 12 years ago

TI__Guru* 84285 points

Interrupt handlers are typically C functions, not C++ functions. In C++, you must declare C functions as 'extern "C"'. Most likely you should be including the header file which defines System_registerIsr in an 'extern "C"' block, like so:

extern "C" {
#include <registerisr.h>
}

Ideally the header file should be taking care of this itself, but often this is overlooked.

0 David Aldrich92784 over 12 years ago in reply to Archaeologist

Genius 3720 points

Thanks for your reply but it has not solved my problem. Please let me restate the problem.

I have an interrupt configuration table that is stored in IsrCfgTable. I have a function called System_registerIsr() that I use to register the ISR's defined in IsrCfgTable. IsrCfgTable, System_registerIsr() and the function that calls System_registerIsr() live in source file isr.cpp. The pertinant code is:

Ctrl_IsrCfgTable    IsrCfgTable[ISR_NUM_ENTRIES] =
{
{INT_COREA, 158, (68+(10*MY_CORE)), 4, &Isr_ulAif2ReceiveQpend},
{INT_COREA, 300, (69+(10*MY_CORE)), 5, &Isr_ulBitReverseQpend},
{INT_COREA, 159, (70+(10*MY_CORE)), 6, &Isr_ulVcpCompletionQpend},
{INT_COREA, 206, (71+(10*MY_CORE)), 7, &Isr_aif2Mntr},
};

void System_registerIsr(uint32 sysEvent, uint32 hostEvent, void (*fxn)(UArg))
{
    int eventId = CpIntc_getEventId(hostEvent);
    CpIntc_dispatchPlug(sysEvent, (CpIntc_FuncPtr)fxn, sysEvent, TRUE);
    CpIntc_mapSysIntToHostInt(0, sysEvent, hostEvent);
    CpIntc_enableHostInt(0, hostEvent);
    CpIntc_enableSysInt(0, sysEvent);
}

void Ctrl_InitInterrupts(void)
{
    Hwi_Params hwiParams;

    // Setup all the necessary mapped interrupts for the relevant cores
    for (uint32 idx=0; idx <ISR_NUM_ENTRIES; idx ++)
    {
        if(IsrCfgTable[idx].intCoreMap == MY_CORE)
        {
            System_registerIsr(IsrCfgTable[idx].systemInterrupt,
                                           IsrCfgTable[idx].hostInterrupt,
                                           IsrCfgTable[idx].isrHandler);          <====== Error

The error for the indicated line is:

argument of type "void (*)(UArg) C" is incompatible with parameter of type "void (*)(UArg)"

As I said above, all the above code is in a .cpp file. How can I resolve this error please?

Best regards

David

0 George Mock over 12 years ago in reply to David Aldrich92784

TI__Guru**** 251180 points

FIrst I'll illustrate your error with a contrived example.

% type file.cpp
void register_isr(void (*fxn)(int));
extern "C" void isr_handler(int);

void do_stuff()
{
   register_isr(isr_handler);
}

% cl6x --verbose_diagnostics file.cpp
"file.cpp", line 6: error: argument of type "void (*)(int) C" is incompatible
          with parameter of type "void (*)(int)"
     register_isr(isr_handler);
                  ^

1 error detected in the compilation of "file.cpp".

>> Compilation failure

The fix is to make the type of the argument to register_isr match with the declaration for isr_handler. There are two ways to do that. One is to make register_isr extern "C".

extern "C" {                               // new code here
   void register_isr(void (*fxn)(int));
}

extern "C" void isr_handler(int);

void do_stuff()
{
   register_isr(isr_handler);
}

The other method is to remove extern "C" from the declaration of isr_handler.

void register_isr(void (*fxn)(int));
void isr_handler(int);                // change here

void do_stuff()
{
   register_isr(isr_handler);
}

I'm not sure which approach is best in your case.

Thanks and regards,

-George

0 David Aldrich92784 over 12 years ago in reply to George Mock

Genius 3720 points

Hi George

Thanks for your answer. My problem is now fixed.

Best regards

David

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Help needed with ISR function ptr compiler error