- if ( membreak == NULL )
- {
- /* first call, make sure end-of-heap is page-aligned */
- intptr_t unaligned = 0;
- membreak = sbrk( 0 );
- unaligned = _PDCLIB_PAGESIZE - (intptr_t)membreak % _PDCLIB_PAGESIZE;
- if ( unaligned < _PDCLIB_PAGESIZE )
- {
- /* end-of-heap not page-aligned - adjust */
- if ( sbrk( unaligned ) != membreak )
- {
- /* error */
- return NULL;
- }
- membreak = (char *)membreak + unaligned;
- }
- }
- /* increasing or decreasing heap - standard operation */
- void * oldbreak = membreak;
- membreak = (void *)( (char *)membreak + ( n * _PDCLIB_PAGESIZE ) );
- if ( brk( membreak ) == 0 )
- {
- /* successful */
- return oldbreak;
- }
- else
- {
- /* out of memory */
- membreak = oldbreak;
- return NULL;
- }