lwpID.cc

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// -*- LSST-C++ -*-
/*
 * LSST Data Management System
 * Copyright 2016 LSST Corporation.
 *
 * This product includes software developed by the
 * LSST Project (http://www.lsst.org/).
 *
 * This program 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.
 *
 * This program 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 LSST License Statement and
 * the GNU General Public License along with this program.  If not,
 * see <http://www.lsstcorp.org/LegalNotices/>.
 */
 
// System Headers
#include <iostream>
#include <string>
#if defined(__linux__)
#include <sys/syscall.h>
#include <unistd.h>
#elif defined(__APPLE__)
#include <pthread.h>
#else
#include <atomic>
#endif
 
namespace lsst {
namespace log {
namespace detail {
 
unsigned lwpID() {
 
#if defined(__linux__)
 
    // On Linux have to do syscall
    auto lwp = syscall(SYS_gettid);
 
#elif defined(__APPLE__)
 
    // OSX has a special Pthreads function to find out PID
    auto lwp = pthread_mach_thread_np(pthread_self());
 
#else
 
    // On all other system just generate incremental number and call it LWP
    static std::atomic<unsigned> threadNum(0);
    thread_local static auto lwp = ++threadNum;
 
#endif
 
    return static_cast<unsigned>(lwp);
}
 
}}} // namespace lsst::log::detail