Why std::this_thread in function fails?

Question

0.00/5 (No votes)

See more:

Why this function fail to compile?
It look innocent enough.
I use it a lot and works fine, but whenever I try to make a function of it, it fails.

C++

#include <iostream>
#include <chrono>
#include <thread>
using namespace std::literals;

void pauseScreen(float &duration) {
	if ( duration == 0.5 ) {
		std::this_thread::sleep_for(0.5s);
	} else if ( duration == 1 ) {
		std::this_thread::sleep_for(1s);
	} else if ( duration == 2 ) {
		std::this_thread::sleep_for(2s);
	} else {
		std::this_thread::sleep_for(4s);
	}
}

int main(){
    std::cout<<"Hello";
    pauseScreen(1);
    return 0;
}

Update: pauseScreen is the exact function from my current project (without other few thousands lines of code). Commenting out this function allow my project to compile. When tested on new blank project, it compiles fine.

What I have tried:

if I remove the function and put
std::this_thread::sleep_for(1s); directly below the the hello message, it compiles.

Posted 17-Feb-16 8:56am

Are Riff

Updated 18-Feb-16 11:57am

v2

Add a Solution

Comments

Andreas Gieriet 17-Feb-16 15:43pm

What is the error message?
Cheers
Andi

Are Riff 17-Feb-16 16:21pm

Binary '+=': no operator found which takes a right-hand operandi of type 'const std::chrono::duration<double,std::ratio<1,1>>'(or there is no acceptable conversion)

1 solution

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Andreas Gieriet · Answer 1 · 2016-02-17T10:04:00

You have several flaws in your code:

You have declared a reference parameter for a fundamental type instead of a value parameter (you do not intend to modify it - so, why a reference parameter?).
You pass an rvalue to an lvalue reference (a literal to a reference) - this is not allowed.
You have a float instead of the double parameter (a floating-point literal is of type double unless you add a float suffix (e.g. 1.0F)).
You pass an int to a float (assuming you replace the float reference by a plain float) - this is not an error, but you add complexity without cause.

How about

C++

void pauseScreen(double duration_in_sec) {
	if ( duration_in_sec == 0.5 ) {
		std::this_thread::sleep_for(0.5s);
	} else if ( duration_in_sec == 1.0 ) {
		std::this_thread::sleep_for(1s);
	} else if ( duration_in_sec == 2.0 ) {
		std::this_thread::sleep_for(2s);
	} else {
		std::this_thread::sleep_for(4s);
	}
}
 
int main(){
    std::cout<<"Hello";
    pauseScreen(1.0);
    return 0;
}

Cheers
Andi