1 /* Copyright (C) 1991-2019 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <https://www.gnu.org/licenses/>. */
21 #include <libc-internal.h>
23 /* Defined in brk.c. */
24 extern void *__curbrk
;
25 extern int __brk (void *addr
);
27 /* Extend the process's data space by INCREMENT.
28 If INCREMENT is negative, shrink data space by - INCREMENT.
29 Return start of new space allocated, or -1 for errors. */
31 __sbrk (intptr_t increment
)
35 /* If this is not part of the dynamic library or the library is used
36 via dynamic loading in a statically linked program update
37 __curbrk from the kernel's brk value. That way two separate
38 instances of __brk and __sbrk can share the heap, returning
39 interleaved pieces of it. */
40 if (__curbrk
== NULL
|| __libc_multiple_libcs
)
41 if (__brk (0) < 0) /* Initialize the break. */
49 ? ((uintptr_t) oldbrk
+ (uintptr_t) increment
< (uintptr_t) oldbrk
)
50 : ((uintptr_t) oldbrk
< (uintptr_t) -increment
))
56 if (__brk (oldbrk
+ increment
) < 0)
61 libc_hidden_def (__sbrk
)
62 weak_alias (__sbrk
, sbrk
)