free() function without malloc or calloc

Question

quick question

Can you use the free() function without having to prior call a malloc ??

ei.

void someFunc( void )
{
   char str[6] = {"Hello"};

   //some processing here ....

   free(str);
}

I get no compiling errors but Does this work or is it correct at all ?

Thank you,

Answer 1

This is not at all correct:

1. You cannot free a static array such as char str[6].
2. free() should only be called on memory you allocated (or on NULL).

Answer 2

When you call malloc() or any other allocation function, memory will be allocated on the heap. This is the only memory that can be freed. When you declare a static string, as you've done in your example, the string is allocated at compile time in another memory segment. The same goes for the str pointer itself which is allocated on the stack, and thus cannot be freed either.