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C stdlib free() Function

❮ C stdlib Library


Example

Free memory when finished using it:

// Allocate memory for a number of items
int numItems = 15;
int *myArray = calloc(numItems, sizeof(int));

// Write into the memory
for(int i = 0; i < numItems; i++) {
  myArray[i] = i + 1;
}

// Display the contents of the memory
for(int i = 0; i < numItems; i++) {
  printf("%d ", myArray[i]);
}

// Free the memory
free(myArray);
myArray = NULL;
Try it Yourself »

Definition and Usage

The free() function deallocates dynamic memory. Dynamic memory is memory which was allocated by the malloc(), calloc() or realloc() functions.

The free() function is defined in the <stdlib.h> header file.

To learn more about memory deallocation, see our C Deallocate Memory tutorial.


Syntax

free(void * ptr);

Parameter Values

Parameter Description
ptr A pointer to a block of dynamic memory.

❮ C stdlib Library

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