too many *'s

ok i just want to double check this

there is a function which reads out an array as

Code:

---

Func ((void **)&Array)

---

but this function is in a library inside another function and i need to pass 'array' out

So this would look like

Code:

---

int otherFunc((void **)Array){
        Func ((void **)&Array)
        ...
        other stuff
        ...
        return 0;
}

---

Which I would call like:

Code:

---

otherFunc((void **)&Array)

---

Is this right... i understand the idea of pointers and addresses but i dont like it when they get mixed with arrays.

Errm... what?

What are the functions and variables declared as and what are you trying to do?

Quote:

---

Originally Posted by chico1st

ok i just want to double check this

there is a function which reads out an array as

Code:

---

Func ((void **)&Array)

---

[/CODE]

---

This is wrong. You're passing the address of the temporary representing the pointer to the array, and passing it to Func.

You're also not following naming conventions.

A function that takes a void ** should take an array of void pointers as its argument.

Quote:

---

Originally Posted by robwhit

Errm... what?

What are the functions and variables declared as and what are you trying to do?

---

Func ((void **)&Array)
Is a function that I have to use from a library which reads data from some hardware that I have

All i want to do is pass on that data as a pointer since i need to access it from another program

This function (otherFunc) will be part of a library which I need.

doesn't Func have a return type?

ok yes int Func

When you have an & in the prototype, that means a reference. And you don't use typecasts in the prototype ((void **)). But references are C++. This is the C board. Are you sure you have the prototype of the function and the right board?

I think that's the call. Otherwise it might look like:

Code:

---

int Func (void *&Array)

---

ok, if it's the call, then what's the prototype?

>ok, if it's the call, then what's the prototype?
Actually you raise an interesting question, because the following isn't even a valid function declaration:

Code:

---

int otherFunc((void **)Array){

---

That what the original post looks like.

Quote:

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Originally Posted by swoopy

>ok, if it's the call, then what's the prototype?
Actually you raise an interesting question, because the following isn't even a valid function declaration:

Code:

---

int otherFunc((void **)Array){

---

That what the original post looks like.

---

So what am I supposed to do?
i am hopelessly confuzed now.

And I am supposed to be writing in C, if i did c++ by accident then thats bad

Can you post the correct (compilable without errors) prototype of Func() - perhaps you can dig out the header file that has the prototype and post the ACTUAL function prototype.

I wrote a bit of code like this:

Code:

---

int func(void **p);

int main()
{
  void *ptr;
 
  func(&ptr);
  return 0;
}

---

It compiles, but doesn't link since I don't have a "func" somewhere.

--
Mats

Code:

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Int32 func(void** Array);

---

if you were to be passing the value for ptr into main what would it look like?

Code:

---

int func(void **p);

int main(*ptr)
{
  func(ptr);
  return 0;
}

---

OR

Code:

---

int func(void *p);

int main(*ptr)
{
  func(&ptr);
  return 0;
}

---

>Int32 func(void** Array);
How is the array you want to pass to this function declared? Is it:

Code:

---

int *num_array;

---

Or:

Code:

---

int **num_array;

---

Or:

Code:

---

int num_array[10];

---

Or:

Code:

---

int *num_array[10];

---

Or is it actually a void **:

Code:

---

void **array;

---

Or something else?

Yes, one of those is right - it depends A LOT on what the function actually expects. It is impossible to say from just seeing the prototype of a function whether it expects the address of a void pointer [and whether it should be a void pointer that points to some valid memory, or if the function just sets the pointer to something within the function], or it expects the address of (for example) an array.

Without either source of func, or the documentation of func, it's not possible for us to say what it does.

--
Mats

array is originally

Code:

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Int8*      Array=NULL;

---

Ok, so it MAY indicate that func() allocates memory for you, and you should pass the address of Array to the function - but I make no guarantees - it may be that you should allocate memory before passing array to func().

--
Mats