Sleep for Milliseconds
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++? 5 20 Answers...
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++?
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.
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);
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.
#include <chrono>
#include <thread>
std::this_thread::sleep_for(std::chrono::milliseconds(1000)); // sleep for 1 second
Remember to import the two headers.
Why don't use time.h library? Runs on Windows and POSIX systems(Don't use this code in production!):
#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.
#include <windows.h>
Syntax:
Sleep ( __in DWORD dwMilliseconds );
Usage:
Sleep (1000); //Sleeps for 1000 ms or 1 sec
From C++14 using std and also its numeric literals:
#include <chrono>
#include <thread>
using namespace std::chrono;
std::this_thread::sleep_for(123ms);
If using MS Visual C++ 10.0, you can do this with standard library facilities:
Concurrency::wait(milliseconds);
you will need:
#include <concrt.h>
On platforms with the select function (POSIX, Linux, and Windows) you could do:
void sleep(unsigned long msec) {
timeval delay = {msec / 1000, msec % 1000 * 1000};
int rc = ::select(0, NULL, NULL, NULL, &delay);
if(-1 == rc) {
// Handle signals by continuing to sleep or return immediately.
}
}
However, there are better alternatives available nowadays.
The way to sleep your program in C++ is the Sleep(int) method. The header file for it is #include "windows.h."
For example:
#include "stdafx.h"
#include "windows.h"
#include "iostream"
using namespace std;
int main()
{
int x = 6000;
Sleep(x);
cout << "6 seconds have passed" << endl;
return 0;
}
The time it sleeps is measured in milliseconds and has no limit.
Second = 1000 milliseconds
Minute = 60000 milliseconds
Hour = 3600000 milliseconds
Select call is a way of having more precision (sleep time can be specified in nanoseconds).
Use Boost asynchronous input/output threads, sleep for x milliseconds;
#include <boost/thread.hpp>
#include <boost/asio.hpp>
boost::thread::sleep(boost::get_system_time() + boost::posix_time::millisec(1000));
The question is old, but I managed to figure out a simple way to have this in my app. You can create a C/C++ macro as shown below use it:
#ifndef MACROS_H
#define MACROS_H
#include <unistd.h>
#define msleep(X) usleep(X * 1000)
#endif // MACROS_H
Elegant solution from the one answer, bit modified.. One can easilly add select() usage if there's no better functionality available. Just make function that uses select() etc. ..
Code:
#include <iostream>
/*
Prepare defines for millisecond sleep function that is cross-platform
*/
#ifdef _WIN32
# include <Windows.h>
# define sleep_function_name Sleep
# define sleep_time_multiplier_for_ms 1
#else
# include <unistd.h>
# define sleep_function_name usleep
# define sleep_time_multiplier_for_ms 1000
#endif
/* Cross platform millisecond sleep */
void cross_platform_sleep_ms(unsigned long int time_to_sleep_in_ms)
{
sleep_function_name ( sleep_time_multiplier_for_ms * time_to_sleep_in_ms );
}
As a Win32 replacement for POSIX systems:
void Sleep(unsigned int milliseconds) {
usleep(milliseconds * 1000);
}
while (1) {
printf(".");
Sleep((unsigned int)(1000.0f/20.0f)); // 20 fps
}
I use this:
#include <thread>
#define sleepms(val) std::this_thread::sleep_for(val##ms)
example:
sleepms(200);
for C use /// in gcc.
#include <windows.h>
then use Sleep(); /// Sleep() with capital S. not sleep() with s .
//Sleep(1000) is 1 sec /// maybe.
clang supports sleep(), sleep(1) is for 1 sec time delay/wait.