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// Copyright 2016 Martin C. Frith
#ifndef THREAD_UTIL_HH
#define THREAD_UTIL_HH
#include <iostream>
#include <stdexcept>
#ifdef HAS_CXX_THREADS
#include <thread>
#endif
namespace cbrc {
inline unsigned decideNumberOfThreads(unsigned request,
const char *programName,
bool isVerbose) {
#ifdef HAS_CXX_THREADS
if (request) return request;
unsigned x = std::thread::hardware_concurrency();
if (x) {
if (isVerbose) std::cerr << programName << ": threads=" << x << '\n';
return x;
}
std::cerr
<< programName
<< ": can't determine how many threads to use: falling back to 1 thread\n";
#else
if (request != 1)
throw
std::runtime_error("I was installed here with multi-threading disabled");
#endif
return 1;
}
}
#endif
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