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HMANAGE.C
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─────Run-Time Library───────────────────────────────────────────────────────
/* HMANAGE.C illustrates heap management using:
* _heapadd _heapmin
*/
#include <stdio.h>
#include <conio.h>
#include <process.h>
#include <malloc.h>
void heapdump( char *msg ); /* Prototype */
char s1[] = { "Here are some strings that we use at first, then don't\n" };
char s2[] = { "need any more. We'll give their space to the heap. \n\n" };
void main()
{
int *p[5], i;
printf( "%s%s", s1, s2 );
heapdump( "Initial heap" );
/* Give space of used strings to heap. */
_heapadd( s1, sizeof( s1 ) );
_heapadd( s2, sizeof( s2 ) );
heapdump( "After adding used strings" );
/* Allocate some blocks. Some may use used string blocks. */
for( i = 0; i < 4; i++ )
if( (p[i] = (int *)calloc( 10 * (i + 1), sizeof( int ) )) == NULL )
{
--i;
break;
}
heapdump( "After allocating memory" );
/* Free some of the blocks. */
free( p[1] );
free( p[2] );
heapdump( "After freeing memory" );
/* Minimize heap. */
_heapmin();
heapdump( "After compacting heap" );
exit( 0 );
}
/* Walk through heap entries, displaying information about each block. */
void heapdump( char *msg )
{
_HEAPINFO hi;
printf( "\n%s\n", msg );
hi._pentry = NULL;
while( _heapwalk( &hi ) == _HEAPOK )
printf( "\t%s block at %Fp of size %u\t\n",
hi._useflag == _USEDENTRY ? "USED" : "FREE",
hi._pentry,
hi._size );
_getch();
}
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