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avr-libc
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setjmp.h
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/* Copyright (c) 2002,2007 Marek Michalkiewicz
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All rights reserved.
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Redistribution and use in source and binary forms, with or without
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modification, are permitted provided that the following conditions are met:
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* Redistributions of source code must retain the above copyright
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notice, this list of conditions and the following disclaimer.
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* Redistributions in binary form must reproduce the above copyright
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notice, this list of conditions and the following disclaimer in
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the documentation and/or other materials provided with the
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distribution.
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* Neither the name of the copyright holders nor the names of
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contributors may be used to endorse or promote products derived
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from this software without specific prior written permission.
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THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE. */
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/* $Id: setjmp.h 1656 2008-03-24 11:29:55Z dmix $ */
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#ifndef __SETJMP_H_
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#define __SETJMP_H_ 1
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#ifdef __cplusplus
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extern
"C"
{
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#endif
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/*
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jmp_buf:
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offset size description
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0 16/4 call-saved registers (r2-r17)
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(AVR tiny10 family has only 4 call saved registers (r18-r21))
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16/4 2 frame pointer (r29:r28)
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18/6 2 stack pointer (SPH:SPL)
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20/8 1 status register (SREG)
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21/9 2/3 return address (PC) (2 bytes used for <=128Kw flash)
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23/24/11 = total size (AVR Tiny10 family always has 2 bytes PC)
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*/
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#if !defined(__DOXYGEN__)
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#if defined(__AVR_TINY__)
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# define _JBLEN 11
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#elif defined(__AVR_3_BYTE_PC__) && __AVR_3_BYTE_PC__
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# define _JBLEN 24
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#else
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# define _JBLEN 23
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#endif
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typedef
struct
_jmp_buf {
unsigned
char
_jb[_JBLEN]; } jmp_buf[1];
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#endif
/* not __DOXYGEN__ */
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/** \file */
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/** \defgroup setjmp <setjmp.h>: Non-local goto
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While the C language has the dreaded \c goto statement, it can only be
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used to jump to a label in the same (local) function. In order to jump
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directly to another (non-local) function, the C library provides the
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setjmp() and longjmp() functions. setjmp() and longjmp() are useful for
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dealing with errors and interrupts encountered in a low-level subroutine
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of a program.
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\note setjmp() and longjmp() make programs hard to understand and maintain.
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If possible, an alternative should be used.
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\note longjmp() can destroy changes made to global register
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variables (see \ref faq_regbind).
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For a very detailed discussion of setjmp()/longjmp(), see Chapter 7 of
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<em>Advanced Programming in the UNIX Environment</em>, by W. Richard
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Stevens.
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Example:
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\code
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#include <setjmp.h>
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jmp_buf env;
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int main (void)
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{
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if (setjmp (env))
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{
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... handle error ...
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}
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while (1)
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{
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... main processing loop which calls foo() some where ...
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}
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}
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...
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void foo (void)
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{
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... blah, blah, blah ...
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if (err)
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{
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longjmp (env, 1);
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}
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}
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\endcode */
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#ifndef __ATTR_NORETURN__
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#define __ATTR_NORETURN__ __attribute__((__noreturn__))
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#endif
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/** \ingroup setjmp
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\brief Save stack context for non-local goto.
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\code #include <setjmp.h>\endcode
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setjmp() saves the stack context/environment in \e __jmpb for later use by
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longjmp(). The stack context will be invalidated if the function which
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called setjmp() returns.
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\param __jmpb Variable of type \c jmp_buf which holds the stack
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information such that the environment can be restored.
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\returns setjmp() returns 0 if returning directly, and
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non-zero when returning from longjmp() using the saved context. */
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extern
int
setjmp
(jmp_buf __jmpb);
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/** \ingroup setjmp
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\brief Non-local jump to a saved stack context.
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\code #include <setjmp.h>\endcode
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longjmp() restores the environment saved by the last call of setjmp() with
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the corresponding \e __jmpb argument. After longjmp() is completed,
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program execution continues as if the corresponding call of setjmp() had
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just returned the value \e __ret.
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\note longjmp() cannot cause 0 to be returned. If longjmp() is invoked
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with a second argument of 0, 1 will be returned instead.
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\param __jmpb Information saved by a previous call to setjmp().
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\param __ret Value to return to the caller of setjmp().
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\returns This function never returns. */
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extern
void
longjmp
(jmp_buf __jmpb,
int
__ret) __ATTR_NORETURN__;
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#ifdef __cplusplus
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}
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#endif
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#endif
/* !__SETJMP_H_ */
Automatically generated by Doxygen 1.8.1.1 on Fri Aug 17 2012.