Deallocating memory with free
In programs that:
- run for a long time
(perhaps long-running server programs such as web-servers), or
- temporarily require a lot of memory, and then no longer require it,
we should deallocate the memory provided to us
by malloc() and calloc().
The C11 standard library provides an obvious function to perform this:
extern void free( void *pointer );
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Any pointer successfully returned by malloc() or
calloc()
may be freed.
Think of it as requesting that some of the allocated heap memory
be given back to the operating system for re-use.
#include <stdlib.h>
int *vector = randomints( 1000 );
if(vector != NULL) {
// USE THE vector
......
free( vector );
}
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Note, there is no need for your programs to completely deallocate
all of their allocated memory before they exit - the operating system
will do that for you.
CITS2002 Systems Programming, Lecture 12, p9, 28th August 2024.
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CITS2002