看如下三段代码：
代码语言：javascript复制// mutex example
#include <iostream> // std::cout
#include <thread> // std::thread
#include <mutex> // std::mutex
std::mutex mtx; // mutex for critical section
void print_block (int n, char c) {
// critical section (exclusive access to std::cout signaled by locking mtx):
mtx.lock();
for (int i=0; i<n; i) { std::cout << c; }
std::cout << 'n';
mtx.unlock();
}
int main ()
{
std::thread th1 (print_block,50,'*');
std::thread th2 (print_block,50,'$');
th1.join();
th2.join();
return 0;
}#include <iostream>
#include <mutex>
#include <thread>
int v = 1;
void critical_section(int change_v) {
static std::mutex mtx;
std::lock_guard<std::mutex> lock(mtx);
// do contention operations
v = change_v;
// mtx will be destructed when exit this region
}
int main() {
std::thread t1(critical_section, 2), t2(critical_section, 3);
t1.join();
t2.join();
std::cout << v << std::endl;
return 0;
}#include <iostream>
#include <mutex>
#include <thread>
int v = 1;
void critical_section(int change_v) {
static std::mutex mtx;
std::unique_lock<std::mutex> lock(mtx);
// do contention operations
v = change_v;
std::cout << v << std::endl;
// release the lock
lock.unlock();
// during this period,
// others are allowed to acquire v
// start another group of contention operations
// lock again
lock.lock();
v = 1;
std::cout << v << std::endl;
}
int main() {
std::thread t1(critical_section, 2), t2(critical_section, 3);
t1.join();
t2.join();
return 0;
}尝试编译无果……
查一下，c 20应该可以。
只能使用如下链接：
coliru.stacked-crooked.com
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