将void（*）（）转换为void（*）（unsigned char）

Question

I'm trying to convert a void (*)() to void (*)(unsigned char) but my knowledge in C++ isn't good enough. I searched, but I could not find any examples. So I thought to create a function of function but I get some error:

typedef void (* voidFuncPtr)();
void castHandler(voidFuncPtr handler)(uint8_t gpio_num)
{
    handler();
}

void attachInterrupt(uint8_t pin, voidFuncPtr handler, int mode)
{
    // typedef void (* voidFuncPtr)();
    // typedef void (* gpio_interrupt_handler_t)(uint8_t gpio_num);
    // typedef void (* gpio_interrupt_handler_t)(unsigned char)
    gpio_set_interrupt(pin, GPIO_INTTYPE_EDGE_ANY, castHandler(handler));
}

error: 'castHandler' declared as function returning a function void castHandler(voidFuncPtr handler)(uint8_t gpio_num)

error: 'castHandler' was not declared in this scope gpio_set_interrupt(pin, GPIO_INTTYPE_EDGE_ANY, castHandler(handler));

Can someone help me?

Answer 1

You need to maintain a table of handlers for each GPIO. Something like the following (untested and incomplete - some initializations and error checking are omitted) code:

typedef void (* voidFuncPtr)();

voidFuncPtr handlers[MAX_HANDLERS];

void attachInterrupt(uint8_t pin, voidFuncPtr handler, int mode)
{
    handlers[pin] = handler;
}

void handleGPIO(unsigned char pin)
{
    if (handlers[pin])
        handlers[pin]();
}

void enableGPIOInterrupts(void)
{
    /// Do this for each available pin
    gpio_set_interrupt(pin, GPIO_INTTYPE_EDGE_ANY, handleGPIO);
}

Answer 2

Why not just write a function to do a redirection ie

void redirectFunction(unsigned char)
{
   handler();
}

then

gpio_set_interrupt(pin, GPIO_INTTYPE_EDGE_ANY,redirectFunction);

EDIT

Perhaps this in C++:

void redirectFunction(std::function<void()> handler, unsigned char)
{
   handler();
}

void wibble() { }

gpio_set_interrupt(pin, GPIO_INTTYPE_EDGE_ANY, 
   std::bind(redirectFunction, _1, wibble)

);