Creating std::thread in Class with Header

Question

How do I initialize DefenseThread so that it will start executing Defend()? I have seen a lot of examples on how to do it from a .cpp file without a header, but non with.

void CommandDefend::DefendStart()

Gets the following error:

'&' requires I-value

Header:

#pragma once

#include <thread>

class CommandDefend : public ICommand
{
public:
CommandDefend();
~CommandDefend();

private:
thread* DefenseThread;

/// <summary>
/// Starts the commands execution.
/// </summary>
void DefendStart();

/// <summary>
/// Does the actual defending.
/// </summary>
void Defend();
};

CPP:

#include "stdafx.h"
#include "CommandDefend.h"


void CommandDefend::DefendStart()
{//ERROR HERE!!!!!!
    DefenseThread = new thread(&CommandDefend::Defend);

}

void CommandDefend::Defend()
{
}

it doesnt have anything to do with or without header. THe problem is that your thread is destroyed when `DefendStart` returns — 463035818_is_not_an_ai, Jul 14 '17 at 14:34
What is your question? 'I need to do this' OK, so does this code not achieve that? Why not? What happens instead? — underscore_d, Jul 14 '17 at 14:47
What line of code produces that error? I don't see anything here that looks like it would. When you post code, you should post a [mcve] — xaxxon, Jul 14 '17 at 14:53
Don't post just part of the error. No compiler would report an error without telling you _where_ it occurred. — underscore_d, Jul 14 '17 at 14:55
void CommandDefend::DefendStart() {//ERROR HERE!!!!!! DefenseThread = new thread(&CommandDefend::Defend); } — SneakyTactician2, Jul 14 '17 at 14:57
so it's a duplicate of [Start thread with member function](https://stackoverflow.com/questions/10673585/start-thread-with-member-function) Please see there how to call the `thread` constructor correctly, and if that fixes your problem, mark your question as a duplicate of that one. — underscore_d, Jul 14 '17 at 15:01
Nope, I have already seen that. The question is not the same, as the class is not defined with a header file, like my class is. — SneakyTactician2, Jul 14 '17 at 15:06
I don't believe that makes any difference at all, nor have you explained why you think it does (hint: if you implemented your class without a header, this syntax still would not work). edit: LOL, and now you've accepted a duplicate answer that says the same thing. I don't even. — underscore_d, Jul 14 '17 at 15:08

score 2 · Accepted Answer · answered Jul 14 '17 at 15:07

If you replace

DefenseThread = new thread(&CommandDefend::Defend);

with

DefenseThread = new thread(&CommandDefend::Defend, this);

it should work, because it's the way how I initialize class members of type std::thread (while they are not pointers).

Creating std::thread in Class with Header

1 Answers1