CODEWITHSUNDEEP
c
AbhishekSaha
AbhishekSaha

Reputation: 745

How to free memory from char array in C

I created a char array like so:

char arr[3] = "bo";

How do I free the memory associated with array I named "arr"?

Upvotes: 45

Views: 153741

Answers (4)

Ramkumar lodhi
Ramkumar lodhi

Reputation: 131

char arr[3] = "bo";

The arr takes the memory into the stack segment. which will be automatically free, if arr goes out of scope.

Upvotes: 2

rullof
rullof

Reputation: 7442

Local variables are automatically freed when the function ends, you don't need to free them by yourself. You only free dynamically allocated memory (e.g using malloc) as it's allocated on the heap:

char *arr = malloc(3 * sizeof(char));
strcpy(arr, "bo");
// ...
free(arr);

More about dynamic memory allocation: http://en.wikipedia.org/wiki/C_dynamic_memory_allocation

Upvotes: 81

David Heffernan
David Heffernan

Reputation: 613531

The memory associated with arr is freed automatically when arr goes out of scope. It is either a local variable, or allocated statically, but it is not dynamically allocated.

A simple rule for you to follow is that you must only every call free() on a pointer that was returned by a call to malloc, calloc or realloc.

Upvotes: 11

Kerrek SB
Kerrek SB

Reputation: 477600

You don't free anything at all. Since you never acquired any resources dynamically, there is nothing you have to, or even are allowed to, free.

(It's the same as when you say int n = 10;: There are no dynamic resources involved that you have to manage manually.)

Upvotes: 15

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