source: mainline/uspace/lib/c/include/setjmp.h@ 1afa94d

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 1afa94d was 91e22dc, checked in by Vojtech Horky <vojtechhorky@…>, 12 years ago

setjmp() shall be a macro according to C standard

As a matter of fact, when it is a function, the context that was
saved may no longer exist. Excerpt from IRC follows:

vhotspur: jermar, hi: what makes you think setjmp needs to be macro
vhotspur: hmmmm, C99 states that setjmp is macro and longjmp is function,

POSIX states that setjmp can be either macro or function

jermar: from what we have learned about context_save over the years
jermar: you basically capture the stack pointer in context_save()
jermar: if it is a function, you immediately deallocate part of that stack
jermar: so later to return to something which has once been a stack,

but is not anymore

jermar: for instance, you could expect to find the return address from

the call to setjmp() on it, but that could have been overwritten
by some further use of the stack

Also fixed bad definition of buffer type.

  • Property mode set to 100644
File size: 2.6 KB
RevLine 
[6cbed012]1/*
2 * Copyright (c) 2008 Josef Cejka
[a070eff]3 * Copyright (c) 2013 Vojtech Horky
[6cbed012]4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 *
10 * - Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer.
12 * - Redistributions in binary form must reproduce the above copyright
13 * notice, this list of conditions and the following disclaimer in the
14 * documentation and/or other materials provided with the distribution.
15 * - The name of the author may not be used to endorse or promote products
16 * derived from this software without specific prior written permission.
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
[d2fa31f7]30/** @addtogroup libc
[6cbed012]31 * @{
32 */
[91e22dc]33/** @file Long jump implementation.
34 *
35 * Implementation inspired by Jiri Zarevucky's code from
36 * http://bazaar.launchpad.net/~zarevucky-jiri/helenos/stdc/revision/1544/uspace/lib/posix/setjmp.h
[6cbed012]37 */
38
[d2fa31f7]39#ifndef LIBC_SETJMP_H_
40#define LIBC_SETJMP_H_
[6cbed012]41
[91e22dc]42#include <libarch/fibril.h>
43
44struct jmp_buf_interal {
45 context_t context;
46 int return_value;
47};
48typedef struct jmp_buf_interal jmp_buf[1];
49
[a070eff]50/*
[91e22dc]51 * Specified as extern to minimize number of included headers
52 * because this file is used as is in libposix too.
53 */
54extern int context_save(context_t *ctx) __attribute__((returns_twice));
55
56/**
57 * Save current environment (registers).
58 *
59 * This function may return twice.
60 *
61 * @param env Variable where to save the environment (of type jmp_buf).
62 * @return Whether the call returned after longjmp.
63 * @retval 0 Environment was saved, normal execution.
64 * @retval other longjmp was executed and returned here.
[a070eff]65 */
[91e22dc]66#define setjmp(env) \
67 ((env)[0].return_value = 0, \
68 context_save(&(env)[0].context), \
69 (env)[0].return_value)
[6cbed012]70
[47b7006]71extern void longjmp(jmp_buf env, int val) __attribute__((noreturn));
[6cbed012]72
73#endif
74
75/** @}
76 */
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