我试图编译这个C ++原子的基本例子&但是当我编译main.cpp文件时,gcc会抛出一些std lib错误 - 这似乎与我的代码无关。
的main.cpp
#include <thread>
#include <atomic>
#include <stdio.h>
#include "randomdelay.h"
using namespace std;
atomic<int> flag;
int sharedValue = 0;
RandomDelay randomDelay1(1, 60101);
RandomDelay randomDelay2(2, 65535);
void IncrementSharedValue10000000Times(RandomDelay& randomDelay)
{
int count = 0;
while (count < 10000000)
{
randomDelay.doBusyWork();
int expected = 0;
if (flag.compare_exchange_strong(expected, 1, memory_order_relaxed))
{
// Lock was successful
sharedValue++;
flag.store(0, memory_order_relaxed);
count++;
}
}
}
void Thread2Func()
{
IncrementSharedValue10000000Times(randomDelay2);
}
int main(int argc, char* argv[])
{
printf("is_lock_free: %s\n", flag.is_lock_free() ? "true" : "false");
for (;;) {
sharedValue = 0;
thread thread2(Thread2Func);
IncrementSharedValue10000000Times(randomDelay1);
thread2.join();
printf("sharedValue=%d\n", sharedValue);
}
return 0;
}
完整代码我使用:https://github.com/preshing/AcquireRelease
这里是gcc错误消息:
[lewis@localhost preshing-AcquireRelease-1422872]$ g++ -std=c++0x -pthread main.cpp
/tmp/cc95LElq.o: In function `IncrementSharedValue10000000Times(RandomDelay&)':
main.cpp:(.text+0xdd): undefined reference to `RandomDelay::doBusyWork()'
/tmp/cc95LElq.o: In function `__static_initialization_and_destruction_0(int, int)':
main.cpp:(.text+0x23d): undefined reference to `RandomDelay::RandomDelay(int, int)'
main.cpp:(.text+0x251): undefined reference to `RandomDelay::RandomDelay(int, int)'
collect2: error: ld returned 1 exit status
这是我使用的命令:g++ -std=c++0x -pthread main.cpp
答案 0 :(得分:2)
RandomDelay
类似乎在randomdelay.cpp
中实现。您必须编译此文件并将其与main.cpp
链接在一起。例如:
$ g++ -std=c++0x -pthread -o program_name main.cpp randomdelay.cpp
答案 1 :(得分:2)
你需要添加包含RandomDelay
定义的cpp文件,例如g++ -std=c++0x -pthread main.cpp randomdelay.cpp