_heapgrw.gml

开放源码的编译器open watcom 1.6.0版的源代码

.func _heapgrow Functions
.func2 _fheapgrow
.func2 _nheapgrow
.ixfunc2 '&Heap' _heapgrow
.ixfunc2 '&Heap' _fheapgrow
.ixfunc2 '&Heap' _nheapgrow
.ixfunc2 '&Memory' _heapgrow
.ixfunc2 '&Memory' _fheapgrow
.ixfunc2 '&Memory' _nheapgrow
#include <malloc.h>
void  _heapgrow( void );
void _nheapgrow( void );
void _fheapgrow( void );
.funcend
.desc begin
The
.kw _nheapgrow
function attempts to grow the near heap to the maximum size of 64K.
You will want to do this in the small data models if you are using both
.kw malloc
and
.kw _fmalloc
or
.kw halloc.
Once a call to
.kw _fmalloc
or
.kw halloc
has been made, you may not be able to allocate any memory with
.kw malloc
unless space has been reserved for the near heap using either
.kw malloc
.ct,
.kw sbrk
or
.kw _nheapgrow.
.np
The
.kw _fheapgrow
function doesn't do anything to the heap because the far heap will be
extended automatically when needed.
If the current far heap cannot be extended, then another far heap will be
started.
.np
In a small data memory model, the &func function is equivalent to the
.kw _nheapgrow
function; in a large data memory model, the &func function is
equivalent to the
.kw _fheapgrow
function.
.desc end
.return begin
These functions do not return a value.
.return end
.see begin
.seelist &function. _heapchk _heapenable _heapgrow _heapmin _heapset _heapshrink _heapwalk
.see end
.exmp begin
#include <stdio.h>
#include <malloc.h>

void main()
  {
    char *p, *fmt_string;
    fmt_string = "Amount of memory available is %u\n";
    printf( fmt_string, _memavl() );
    _nheapgrow();
    printf( fmt_string, _memavl() );
    p = (char *) malloc( 2000 );
    printf( fmt_string, _memavl() );
  }
.exmp output
Amount of memory available is 0
Amount of memory available is 62732
Amount of memory available is 60730
.exmp end
.class WATCOM
.system