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─────Run-Time Library───────────────────────────────────────────────────────
 
/* HANDLER.CPP: This program uses the C++ specific _set_new_handler
 * function to print an error message when the new operator fails.
 * It is important to note that this program uses the new operator
 * to allocate memory from the program heap until no memory is left
 * for allocation.
 */
#include <stdlib.h>
#include <stdio.h>
#include <new.h>
 
/* Allocate memory in blocks of size MemBlock. */
const signed short MemBlock = 2048;
 
/* The handle_heap_depletion function is a customized function that
 * takes action when the new operator can no longer allocate memory
 * from the heap.
 */
int handle_heap_depletion( size_t );
 
void main( void )
{
    /* Register, with the run-time system, the existence of a custom
     * memory handler by passing it to the _set_new_handler function.
     */
    _set_new_handler( handle_heap_depletion );
 
    /* Empty the heap so that the new operator will call the
     * custom function, handle_heap_depletion.
     */
    size_t *pmemdump;
    if(( pmemdump = new size_t[MemBlock] ) == 0 )
        exit( 0 );
    else
        for( ; pmemdump != 0; pmemdump = new size_t[MemBlock] );
}
 
int handle_heap_depletion( size_t size )
{
    /* The handle_heap_depletion function is activated, automatically,
     * when the new operator can no longer allocate memory. The size_t
     * argument is required; its value is the size of the memory block
     * that was last requested from the new operator.
     */
    printf( "Allocation failed, " );
    printf( "%i bytes not available.\n", size );
    /* Tell the new operator to stop allocation attempts. The new
     * operator will continue attempts to allocate memory for return
     * values from this function other than 0.
     */
    return 0;
}
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