Sleep for milliseconds
Sleep for milliseconds
Question
I know the POSIX sleep(x) function makes the program sleep for x seconds. Is there a function to make the program sleep for x milliseconds in C++?
Accepted Answer
Note that there is no standard C API for milliseconds, so (on Unix) you will have to settle for usleep, which accepts microseconds:
#include <unistd.h>
unsigned int microseconds;
...
usleep(microseconds);
Popular Answer
In C++11, you can do this with standard library facilities:
#include <chrono>
#include <thread>
std::this_thread::sleep_for(std::chrono::milliseconds(x));
Clear and readable, no more need to guess at what units the sleep() function takes.
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To stay portable you could use Boost::Thread for sleeping:
#include <boost/thread/thread.hpp>
int main()
{
//waits 2 seconds
boost::this_thread::sleep( boost::posix_time::seconds(1) );
boost::this_thread::sleep( boost::posix_time::milliseconds(1000) );
return 0;
}
This answer is a duplicate and has been posted in this question before. Perhaps you could find some usable answers there too.
Depending on your platform you may have usleep or nanosleep available. usleep is deprecated and has been deleted from the most recent POSIX standard; nanosleep is preferred.
Why don't use time.h library? Runs on Windows and POSIX systems:
#include <iostream>
#include <time.h>
using namespace std;
void sleepcp(int milliseconds);
void sleepcp(int milliseconds) // Cross-platform sleep function
{
clock_t time_end;
time_end = clock() + milliseconds * CLOCKS_PER_SEC/1000;
while (clock() < time_end)
{
}
}
int main()
{
cout << "Hi! At the count to 3, I'll die! :)" << endl;
sleepcp(3000);
cout << "urrrrggghhhh!" << endl;
}
Corrected code - now CPU stays in IDLE state [2014.05.24]:
#include <iostream>
#ifdef _WIN32
#include <windows.h>
#else
#include <unistd.h>
#endif // _WIN32
using namespace std;
void sleepcp(int milliseconds);
void sleepcp(int milliseconds) // Cross-platform sleep function
{
#ifdef _WIN32
Sleep(milliseconds);
#else
usleep(milliseconds * 1000);
#endif // _WIN32
}
int main()
{
cout << "Hi! At the count to 3, I'll die! :)" << endl;
sleepcp(3000);
cout << "urrrrggghhhh!" << endl;
}
nanosleep is a better choice than usleep - it is more resilient against interrupts.