#include <lib.h>
#define sbrk	_sbrk
#include <unistd.h>

extern char *_brksize;

PUBLIC char *sbrk(incr)
int incr;
{
  char *newsize, *oldsize;

  oldsize = _brksize;
  newsize = _brksize + incr;
  if ((incr > 0 && newsize < oldsize) || (incr < 0 && newsize > oldsize))
	return( (char *) -1);
  if (brk(newsize) == 0)
	return(oldsize);
  else
	return( (char *) -1);
}