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ab26a24a | 1 | /* Copyright (C) 1991,1995,1996,1997,2000,2002 Free Software Foundation, Inc. |
478b92f0 | 2 | This file is part of the GNU C Library. |
28f540f4 | 3 | |
478b92f0 | 4 | The GNU C Library is free software; you can redistribute it and/or |
41bdb6e2 AJ |
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. | |
28f540f4 | 8 | |
478b92f0 UD |
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 | |
41bdb6e2 | 12 | Lesser General Public License for more details. |
28f540f4 | 13 | |
41bdb6e2 AJ |
14 | You should have received a copy of the GNU Lesser General Public |
15 | License along with the GNU C Library; if not, write to the Free | |
16 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA | |
17 | 02111-1307 USA. */ | |
28f540f4 | 18 | |
683158e0 RM |
19 | #include <unistd.h> |
20 | #include <errno.h> | |
28f540f4 RM |
21 | |
22 | /* Defined in brk.c. */ | |
683158e0 RM |
23 | extern void *__curbrk; |
24 | extern int __brk (void *addr); | |
28f540f4 | 25 | |
ab26a24a UD |
26 | /* Defined in init-first.c. */ |
27 | extern int __libc_multiple_libcs attribute_hidden; | |
a8874ead | 28 | |
28f540f4 RM |
29 | /* Extend the process's data space by INCREMENT. |
30 | If INCREMENT is negative, shrink data space by - INCREMENT. | |
31 | Return start of new space allocated, or -1 for errors. */ | |
683158e0 | 32 | void * |
0ed99ce4 | 33 | __sbrk (intptr_t increment) |
28f540f4 | 34 | { |
683158e0 RM |
35 | void *oldbrk; |
36 | ||
a8874ead UD |
37 | /* If this is not part of the dynamic library or the library is used |
38 | via dynamic loading in a statically linked program update | |
39 | __curbrk from the kernel's brk value. That way two separate | |
40 | instances of __brk and __sbrk can share the heap, returning | |
41 | interleaved pieces of it. */ | |
39778c6c | 42 | if (__curbrk == NULL || __libc_multiple_libcs) |
14bab8de UD |
43 | if (__brk (0) < 0) /* Initialize the break. */ |
44 | return (void *) -1; | |
28f540f4 RM |
45 | |
46 | if (increment == 0) | |
47 | return __curbrk; | |
48 | ||
49 | oldbrk = __curbrk; | |
683158e0 RM |
50 | if (__brk (oldbrk + increment) < 0) |
51 | return (void *) -1; | |
28f540f4 RM |
52 | |
53 | return oldbrk; | |
54 | } | |
37ba7d66 | 55 | libc_hidden_def (__sbrk) |
28f540f4 | 56 | weak_alias (__sbrk, sbrk) |