C++ std::chrono 的问题
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Problems with std::chrono
提问by Jehan
I am having trouble compiling with chrono, here is the code:
我在用 chrono 编译时遇到问题，这是代码：
Time.hh
时间.hh
#include <chrono>
class Time
{
protected:
std::chrono::steady_clock::time_point _start_t;
std::chrono::steady_clock::time_point _now;
std::chrono::steady_clock::time_point _time;
public:
Time();
Time(const Time &other);
Time &operator=(const Time &other);
~Time();
public:
void start();
double getDurSec();
double getDurMilSec();
private:
void setNow();
};
Compilation error:
编译错误：
g++ -W -Wall -Wextra -I./include -std=c++0x -c -o src/Time/Time.o src/Time/Time.cpp
In file included from src/Time/Time.cpp:11:0:
./include/Time/Time.hh:21:3: error: ‘steady_clock' in namespace ‘std::chrono' does not name a type
./include/Time/Time.hh:22:3: error: ‘steady_clock' in namespace ‘std::chrono' does not name a type
./include/Time/Time.hh:23:3: error: ‘steady_clock' in namespace ‘std::chrono' does not name a type
src/Time/Time.cpp: In member function ‘void Time::start()':
src/Time/Time.cpp:34:2: error: ‘_time' was not declared in this scope
src/Time/Time.cpp:34:23: error: ‘std::chrono::steady_clock' has not been declared
Etc...
等等...
Tell me if you need more informations.
如果您需要更多信息，请告诉我。
回答by Jehan
You are probably using a g++ version prior to 4.7.0 where std::chrono::steady_clockwas not implemented. If this is the case, you have two solutions:
您可能正在使用std::chrono::steady_clock未实现的4.7.0 之前的 g++ 版本。如果是这种情况，您有两种解决方案：
- Upgrade your g++ to 4.7.0 or a more recent version.
- Use instead the old
std::chrono::monotonic_clock.
- 将您的 g++ 升级到 4.7.0 或更新的版本。
- 改用旧的
std::chrono::monotonic_clock.
