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

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.
--
Your C++ comment up-thread BTW is off-topic here. My favourite C++ container is vector, and that has a reserve call so you can keep growing the container without lots of reallocations.