klibc/klibc/sbrk.c

   1 /* sbrk.c - Change data segment size */
   2
   3 /* Written 2000 by Werner Almesberger */
   4
   5 #include <stddef.h>
   6 #include <unistd.h>
   7 #include <sys/types.h>
   8
   9 char *__current_brk;            /* Common with brk.c */
  10
  11 void *sbrk(ptrdiff_t increment)
  12 {
  13   char *old_brk, *new_brk;
  14
  15   if (!__current_brk)
  16     __current_brk = __brk(NULL);
  17   new_brk = __brk(__current_brk+increment);
  18   if (new_brk != __current_brk+increment)
  19     return (void *) -1;
  20   old_brk = __current_brk;
  21   __current_brk = new_brk;
  22   return old_brk;
  23 }