xref: /plan9/sys/src/libc/9sys/sbrk.c (revision 5e91980f0bca263e952809e3dc0cfc5dde74b999) 
1 #include <u.h>
2 #include <libc.h>
3 
4 extern	char	end[];
5 static	char	*bloc = { end };
6 extern	int	brk_(void*);
7 
8 enum
9 {
10 	Round	= 7
11 };
12 
13 int
brk(void * p)14 brk(void *p)
15 {
16 	uintptr bl;
17 
18 	bl = ((uintptr)p + Round) & ~Round;
19 	if(brk_((void*)bl) < 0)
20 		return -1;
21 	bloc = (char*)bl;
22 	return 0;
23 }
24 
25 void*
sbrk(ulong n)26 sbrk(ulong n)
27 {
28 	uintptr bl;
29 
30 	bl = ((uintptr)bloc + Round) & ~Round;
31 	if(brk_((void*)(bl+n)) < 0)
32 		return (void*)-1;
33 	bloc = (char*)bl + n;
34 	return (void*)bl;
35 }
36