Re: realloc() - frequency, conditions, or experiences about relocation?

Am 25.06.2024 um 12:55 schrieb Vir Campestris:

On 25/06/2024 09:48, Bonita Montero wrote:

Test this code with your Linux installation. For my installation
glibc does all realloc()ations in-place. Really surprising for me.
>
#include <stdio.h>
#include <stdlib.h>
>
int main()
{
     void *p = malloc( 0x100000000 );
     printf( "%p\n", p );
     p = realloc( p, 1 );
     printf( "%p\n", p );
     malloc( 0x100000000 - 0x10000 );
     p = realloc( p, 0x100000000 );
     printf( "%p\n", p );
}

Try allocating a bunch of little items, and looking at where they are. They'll likely be contiguous, or evenly spaced, depending on your implementation and what "little" is.
 Then resize them all. Some will move.
 Andy.

The interesting part is that after doing the first realloc()
the memory being freee isn't reused for the next malloc().