69 lines
1.6 KiB
C++
69 lines
1.6 KiB
C++
// include/Yield.hh
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// This file is part of libpbe; see http://svn.chezphil.org/libpbe/
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// (C) 2008 Philip Endecott
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// This program is free software; you can redistribute it and/or modify
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// it under the terms of the GNU General Public License as published by
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// the Free Software Foundation; either version 2 of the License, or
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// any later version.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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#ifndef libpbe_Yield_hh
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#define libpbe_Yield_hh
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// The file implements a Futex-like class which simply calls sched_yield().
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#include <sched.h>
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#include "Exception.hh"
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#include "compiler_magic.hh"
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namespace pbe {
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struct Yield {
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Yield(PBE_UNUSED_ARG(int& val)) {}
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~Yield() {}
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void wait(PBE_UNUSED_ARG(int expected)) {
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int r = ::sched_yield();
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if (r==-1) {
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throw_ErrnoException("futex(FUTEX_WAIT)");
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}
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}
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bool timed_wait(PBE_UNUSED_ARG(int expected), const timespec& timeout) {
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// TODO detect timeout
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wait(expected);
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return true;
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}
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bool timed_wait(PBE_UNUSED_ARG(int expected), float timeout) {
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// TODO detect timeout
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wait(expected);
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return true;
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}
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// Wake up to n waiters; returns the number woken.
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int wake(int n=1) {
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// Hmm, how much does the return value matter?
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return n;
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}
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};
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};
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#endif
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