Bari Wiki

• vyraz s hodnotou ..-2,-1,1,2.. se vyhodnocuje jako true, pouze hodnota 0 je jako false

• volá se při kompilaci!!!
• tj neumožňuje zjistit velikost dynamicky vytvořeného pole, ale pouze pseudo dynamického (nějakým způsobem odvoditelný).
• příklad:

  static unsigned char testArr[] = { 0xaa, 0xbb, 0xcc };
  int size1,size2;
  ..
  int main() {
    size1 = sizeOf(testArr);
    func1(testArr);
  }

  void func1(unsigned char *arr) {
    size2 = sizeof(arr);
  }

• size1 = 3 (bajty), size2 = 8 (bajtu) - tj velikost pointeru na unsigned char

int i;
for (i=0;i<40;i++) {
	printf("%02X ", ((unsigned char*)buffer)[i] );
	if (((i+1)%16) == 0) printf("\n");
}
printf("\n");	 	

Read it backwards (as driven by Clockwise/Spiral Rule)…

int* // pointer to int
int const * // pointer to const int
int * const // const pointer to int
int const * const // const pointer to const int

Now the first const can be on either side of the type so:

const int * // == int const *
const int * const // == int const * const

If you want to go really crazy you can do things like this:

int ** // pointer to pointer to int
int ** const // a const pointer to a pointer to an int
int * const * // a pointer to a const pointer to an int
int const ** // a pointer to a pointer to a const int
int * const * const // a const pointer to a const pointer to an int

And to make sure we are clear on the meaning of const

const int* foo;
int *const bar; //note, you actually need to set the pointer 
                //here because you can't change it later ;)

foo is a variable pointer to a constant int. This lets you change what you point to but not the value that you point to. Most often this is seen with cstrings where you have a pointer to a const char. You may change which string you point to but you can't change the content of these strings. This is important when the string itself is in the data segment of a program and shouldn't be changed.

bar is a const or fixed pointer to a value that can be changed. This is like a reference without the extra syntactic sugar. Because of this fact, usually you would use a reference where you would use a T* const pointer unless you need to allow null pointers.

• jsou závislé na typu
• přičítání

void *p=0;
uint32_t *u=0;
 
printf("%d", p);   // 0
printf("%d", ++p); // 1 !!
 
printf("%d", u);   // 0
printf("%d", ++u); // 4 !!

• rozdíl

void *p=0, *p2=4;
uint32_t *u=0, *u2=4;
 
printf("%d", p2-p);  // 4
printf("%d", u2-u);  // 1 !!