Question

I’m trying to free up RAM by removing a variable after it is used with the free() function, yet my RAM is not cleaning up. I suppose there is no garbage cleanup taking place? The space cleans up after I exit the section of code (scoped if-statement, while-loop or function), but not the free() statement itself.

I’m doing the following to check the RAM:

int freeRam () {
  extern int __heap_start, *__brkval; 
  int v; 
  return (int) &v - (__brkval == 0 ? (int) &__heap_start : (int) __brkval); 
}

Additionally, how would one ‘free’ up such memory?

Answer 1

You can’t expect the __brkval to decrease just because you called free() on a single memory block. The memory block will be marked as free and available for reuse, but in general the __brkval will only move in one direction according to the maximum amount of memory that your program uses at any one time.