why when implement interrupt handler in qt give beolw error ? How to resolve it ?

Qt embedded developer

error: ISO C++ forbids taking the address of an unqualified or parenthesized non-static member function to form a pointer to member function. Say '&MainWindow::gpo_handler' [-fpermissive]
while(ST25DV_GPO_interrupt_init(&gpo_handler) != NFCTAG_OK);
^

error: cannot convert 'void (MainWindow::)()' to 'interrupt_handler_t {aka void ()()}' for argument '1' to 'int32_t ST25DV_GPO_interrupt_init(interrupt_handler_t)'
while(ST25DV_GPO_interrupt_init(&gpo_handler) != NFCTAG_OK);

jsulm

@Qt-embedded-developer Use a normal function as interrupt handler, not a method in a class. In that function you can then call methods of your class if you need to do so.

JonB

@Qt-embedded-developer
So what type is/what is your declaration of your gpo_handler?

Qt embedded developer

@JonB

Declaration is

void gpo_handler(void);

And defination is

void MainWindow::gpo_handler()
{

       ST25DV_FIELD_STATUS fieldpresence;

         BSP_NFCTAG_GetRFField_Dyn(0, &fieldpresence );
   //printf("fielpresence enum = %d", fieldpresence);
         if( fieldpresence == ST25DV_FIELD_ON )
         {
            printf ("GPO handler: field is ON\r\n");
         }
         else
         {

            printf ("GPO handler: field is OFF\r\n");
         }

         uint8_t itstatus;

        // if( GPO_Activated == 1 )
        // {
           //GPO_Activated = 0;

           ST25_RETRY(BSP_NFCTAG_ReadITSTStatus_Dyn(0, &itstatus ));

           if( (itstatus & ST25DV_ITSTS_DYN_FIELDFALLING_MASK) == ST25DV_ITSTS_DYN_RFWRITE_MASK )
           {
             printf("RF write");
           }
           else
               printf(" %x",(itstatus & ST25DV_ITSTS_DYN_FIELDFALLING_MASK));
       //}



}

JonB

@Qt-embedded-developer
So doesn't the error message tell you exactly it wants &MainWindow::gpo_handler?

P.S.

void gpo_handler(void);

That's C-ish. C++ is happy with void gpo_handler();.

Qt embedded developer

@JonB

first error resolved but 2nd error still come

error: cannot convert 'void (MainWindow::)()' to 'interrupt_handler_t {aka void ()()}' for argument '1' to 'int32_t ST25DV_GPO_interrupt_init(interrupt_handler_t)'
while(ST25DV_GPO_interrupt_init(&gpo_handler) != NFCTAG_OK);

jsulm

@Qt-embedded-developer It looks like the interrupt handler takes an int32_t parameter.
Check the interrupt_handler_t data type.

JonB

@jsulm
From the error message (aka void ()()) and from looking at definitions of interrupt_handler_t on the web I do not think that is so. It seems to be

typedef void @far (*interrupt_handler_t)(void);

This is beyond my expertise of C++ now, but is there a problem with passing a C++ member function here??

jsulm

@JonB @Qt-embedded-developer I don't think a method can be used here as interrupt handler. @Qt-embedded-developer use a normal function and call your MainWindow there (also, it is strange that MainWindow handles interrupts).

Qt embedded developer

@jsulm said in why when implement interrupt handler in qt give beolw error ? How to resolve it ?:

interrupt_handler_t

This 3 thing is related to your question and my 2nd error.

1] in source.h
static interrupt_handler_t interrupt_handler;

2] in source.c
typedef void (*interrupt_handler_t)(void) ;

3] in source.c

int32_t ST25DV_GPO_interrupt_init(interrupt_handler_t fh)
{
    pthread_t intr_thread;
    struct sched_param params;
    int ret;

    if(fh == NULL)
    {
        fprintf(stderr,"Handler is not set\r\n");
        return ERR_PARAM;
    }
    interrupt_handler = fh;

    /* create a pthread to poll for interrupt */
    ret = pthread_create(&intr_thread, NULL, ST25DV_GPO_pthread_func, NULL);
    if (ret) {
        fprintf(stderr, "Error: poll thread creation %d\r\n", ret);
        return ERR_IO;
    }

    /* Assign highest priority to polling thread */
    params.sched_priority = sched_get_priority_max(SCHED_FIFO);
    ret = pthread_setschedparam(intr_thread, SCHED_FIFO, &params);
    if (ret) {
        fprintf(stderr,"Error: assigning high priority to polling thread\r\n");
        return ERR_IO;
    }

    return ERR_NONE;
}

jsulm

@Qt-embedded-developer said in why when implement interrupt handler in qt give beolw error ? How to resolve it ?:

typedef void (*interrupt_handler_t)(void) ;

This is a function pointer type, not a pointer to a method, so you can't use a method as interrupt handler. Use a normal function.

JonB

@jsulm said in why when implement interrupt handler in qt give beolw error ? How to resolve it ?:

This is a function pointer type, not a pointer to a method

This is kind of what I thought/asked you.

I am not familiar with this distinction between "a function pointer type" versus "a pointer to a method". Could you explain, or point me to a description, please?

EDIT
Ah, is this to do with class (non-static) method will need an instance and of course that is not appropriate here?

jsulm

@JonB Well, method pointers are funny:

typedef void (MainWindow::*MethodPointer)();
MethodPointer p = &MainWindow::doSomething;
// Calling
(this->*p)();

jsulm

@JonB said in why when implement interrupt handler in qt give beolw error ? How to resolve it ?:

Ah, is this to do with class (non-static) method will need an instance and of course that is not appropriate here?

Yes, you need an instance.

JonB

@jsulm
I did a Google and came up with https://isocpp.org/wiki/faq/pointers-to-members#fnptr-vs-memfnptr-types

Is the type of “pointer-to-member-function” different from “pointer-to-function”?
Yep.

Consider the following function:

int f(char a, float b);
The type of this function is different depending on whether it is an ordinary function or a non-static member function of some class:

Its type is “int ()(char,float)” if an ordinary function
Its type is “int (Fred::)(char,float)” if a non-static member function of class Fred
Note: if it’s a static member function of class Fred, its type is the same as if it were an ordinary function: “int (*)(char,float)”.

Separately:

Yes, you need an instance.

Yes, that's kind of a different issue, in that it's not going to work anyway for the OP. But I was concentrating on the compiler error message.

Qt embedded developer

@JonB So How to implement the interrupt handler for any i2c device using qt ?

jsulm

@Qt-embedded-developer Use a normal function as interrupt handler, not a method in a class. In that function you can then call methods of your class if you need to do so.