[solved] usleep issue in loop C++

mazhar · 2016-07-31 17:58:58

Hi there, im observing issue with usleep. For example in this code:

#include <stdio.h>
#include <iostream>
#include <unistd.h>
using namespace std;

int main() {
for(int i=0;i<100;i++) {
                cout<<i+1;
                unsigned int sleep_time = 100000; 
                usleep(sleep_time);
}
return 0;
}

The problem:
program wont write output then sleep then next output, instead it waits a long time then shows all outputs in once.
What should i do?

Last edited by mazhar (2016-08-01 16:47:30)

stronnag · 2016-07-31 19:00:19

no, you're observing buffered output

The Infinity · 2016-07-31 23:21:23

Just add << std::flush to cout line.

mazhar · 2016-08-01 05:06:14

The Infinity wrote:

Just add << std::flush to cout line.

Thanks, it totally works. is this an obvious concept? what should i read about it?

Trilby · 2016-08-01 10:13:57

stronnag wrote:

you're observing buffered output

It would also "work" if you added a newline after each number.

Arch Linux

#1 2016-07-31 17:58:58

[solved] usleep issue in loop C++

#2 2016-07-31 19:00:19

Re: [solved] usleep issue in loop C++

#3 2016-07-31 23:21:23

Re: [solved] usleep issue in loop C++

#4 2016-08-01 05:06:14

Re: [solved] usleep issue in loop C++

#5 2016-08-01 10:13:57

Re: [solved] usleep issue in loop C++

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