Passing a function pointer and a data pointer argument to a function that takes function pointer wit-CodePudding

from main I'm trying to pass a function with an address to a struct to another function I'm able to edit that takes a function pointer with a aoid pointer as an argument the function I'm trying to pass to attachReleased in main is tareFunc():

attachReleased(&Btn0Params,  tareFunc(&hx711));

and here's the code in another C file:

void attachReleased(btn_params_t *BtnParams, void (*BtnISR)(void *args)){
  // printf("Attached pin #%d\n ", BtnParams->BtnPin);
  BtnParams->ReleasedISR = BtnISR(&args);
  gpio_isr_handler_add(BtnParams->BtnPin, buttonISR, (btn_params_t *)BtnParams);
}

Is it possible to do what I'm trying to achieve with passing the function pointer and the argument pointer at the same time or do you have to separate them which is a little inconvenient?

CodePudding user response：

You're not actually passing a function pointer and its arguments here:

attachReleased(&Btn0Params,  tareFunc(&hx711));

What you're actually doing is calling tareFunc and passing its return value to attachReleased

You need to pass the parameter to tareFunc as a separate argument to attachReleased.

void attachReleased(btn_params_t *BtnParams, void (*BtnISR)(void *), void *args){
  // printf("Attached pin #%d\n ", BtnParams->BtnPin);
  //BtnParams->ReleasedISR = BtnISR(args);
  BtnISR(args);
  gpio_isr_handler_add(BtnParams->BtnPin, buttonISR, (btn_params_t *)BtnParams);
}

Which can then be called like this:

attachReleased(&Btn0Params,  tareFunc, &hx711);

Note also that since the function pointer BtnISR has a void return type, that there's no value to return and use.

CodePudding user response：

As coded you are passing the value returned by tareFunc to attachReleased so unless tareFunc returns void (*BtnISR)(void *args). It isn't possible to pass the value and the function ptr in this way. You could pass the arguments to the func ptr as an additional argument.

CodePudding user response：

If I understand your question correctly, what you want is something like this in your first file:

attachReleased(&Btn0Params, &tareFunc, &hx711);

and like this in your other C file:

void attachReleased(btn_params_t *BtnParams, void (*BtnISR)(void *), void *args)){
  // printf("Attached pin #%d\n ", BtnParams->BtnPin);
  BtnParams->ReleasedISR = (*BtnISR)(args);
  gpio_isr_handler_add(BtnParams->BtnPin, buttonISR, (btn_params_t *)BtnParams);
}