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========= |
\\ / F ield | OpenFOAM: The Open Source CFD Toolbox
\\ / O peration | Website: https://openfoam.org
\\ / A nd | Copyright (C) 2011-2020 OpenFOAM Foundation
\\/ M anipulation |
-------------------------------------------------------------------------------
License
This file is part of OpenFOAM.
OpenFOAM is free software: you can redistribute it and/or modify it
under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
OpenFOAM is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
for more details.
You should have received a copy of the GNU General Public License
along with OpenFOAM. If not, see <http://www.gnu.org/licenses/>.
Class
Foam::timer
Description
Implements a timeout mechanism via sigalarm.
Example usage:
\code
timer myTimer(5); // 5 sec
..
if (timedOut(myTimer))
{
// timed out
}
else
{
// do something possible blocking
}
\endcode
Constructor set signal handler on sigalarm and alarm(). Destructor
clears these.
timedOut is macro because setjmp can't be in member function of timer.
?something to do with stack frames.
Warning
The setjmp restores complete register state so including local vars
held in regs. So if in blocking part something gets calced in a stack
based variable make sure it is declared 'volatile'.
SourceFiles
timer.C
\*---------------------------------------------------------------------------*/
#ifndef timer_H
#define timer_H
#include "className.H"
#include <signal.h>
#include <setjmp.h>
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
//- Check it a timeout has occurred
// keep setjmp in same stack frame so no function calls
#define timedOut(x) \
(((x).newTimeOut_ > 0) ? setjmp(Foam::timer::envAlarm) : false)
namespace Foam
{
/*---------------------------------------------------------------------------*\
Class timer Declaration
\*---------------------------------------------------------------------------*/
class timer
{
// Private Data
//- Old signal masks
static struct sigaction oldAction_;
//- Old alarm() value
static unsigned int oldTimeOut_;
// Private Member Functions
//- Alarm handler
static void signalHandler(int);
public:
// Public data
//- Declare name of the class and its debug switch
ClassName("timer");
//- Current time out value. Needed by macro timedOut
unsigned int newTimeOut_;
//- State for setjmp. Needed by macro timedOut
static jmp_buf envAlarm;
// Constructors
//- Construct from components.
// newTimeOut=0 makes it do nothing.
timer(const unsigned int newTimeOut);
//- Destructor
~timer();
};
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
} // End namespace Foam
// * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * //
#endif
// ************************************************************************* //
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