sbrk.c

实用的程序代码

/*-----------------------------------------------------------------------------
//     $Date: 2002/09/16 21:19:30 $
//     $RCSfile: sbrk.c,v $
//-----------------------------------------------------------------------------
//
// $xilinx_legal_disclaimer
//
//---------------------------------------------------------------------------*/

#include <errno.h>

extern char _heap_start[];
extern char _heap_end[];

static char *heap_ptr;

char *sbrk (int nbytes)
{
  char *base;

  if (!heap_ptr)
    heap_ptr = (char *)&_heap_start;
  base = heap_ptr;
  heap_ptr += nbytes;

  if (heap_ptr <= (char *)&_heap_end)
    return base;
  else
  {
    errno = ENOMEM;
    return ((char *)-1);
  }
}