std::thread question

angus725 (2)
So, with about a semesters worth of C knowledge, I decided to get into C++ in the past few weeks. After a much smaller program that prints a few numbers (without the use of classes), I decided to figure out just how far I can get before I get stuck somewhere with my next program.

Ended up hitting a problem at std::thread, and could not figure out how to fix the compile time error.

A few reference pieces of code (no errors here):

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enum buildingstatus
{
	NONE,
	BUILDING,
	BUILT,
};

class BuildTimerStruct
{
public:
	int TotalTime;
	int* timelefttimer;
	int buildingid;
	BuildTimerStruct();
	~BuildTimerStruct();
};

BuildTimerStruct::~BuildTimerStruct()
{
	delete this;
}

 class Planet
	{
	public:
		Planet();
		~Planet();
		void build();
		void DisplayStats();
		int PlanetID;
		static int globalplanets;
		void BuildingBuilt(int buildingtype);
		void DisplayBuildings();
		void Planet::BuildingTimer (BuildTimerStruct);
		void Planet::TimeUntilCompleteion(const int , const std::string );


	private:
		std::string name;
		buildingstatus *building;
		int timeleft;
		friend class GameSystem;
	};


Compile time error occurs at the std::thread declaration.

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void Planet::build()
{
	int buildinginput=-1;
	std::cout << "Building menu initiated on planet " << name << "." << std::endl;
	DisplayBuildings();
	for(int ii=0; ii < MaxBuildingSelection; ii++)
		std::cout << "To build " << BLDGID(ii) << ", " << "please type in \"" << ii << "\"." << std::endl;
	std::cout << "To exit the building menu, please type in 0." << std::endl;

	while(buildinginput!=0)
	{
		std::cin >> buildinginput;

		if (buildinginput>9000)
		{
				DisplayBuildings();
				for(int iii=0; iii < MaxBuildingSelection; iii++)
					std::cout << "To build " << BLDGID(iii) << ", " << "please type in \"" << iii << "\"." << std::endl;
		}

		else if (buildinginput>0&&buildinginput<MaxBuildingSelection) 
		{
			if (building[buildinginput]!=NONE)
			{
				BuildingBuilt(buildinginput);
			}
			else
			{
				BuildTimerStruct* tempBLDGTIMER = new BuildTimerStruct;
				tempBLDGTIMER->TotalTime=(BLDGTIME(buildinginput));
				tempBLDGTIMER->timelefttimer=&timeleft;
				tempBLDGTIMER->buildingid=buildinginput;
				std::thread foo(&Planet::BuildingTimer, *tempBLDGTIMER); //Compile time error
				foo.detach();
				buildinginput=0;
				break; //to skip the rest of the junk 
			}
		}
		else
			std::cout <<"No building or invalid number selected, ";

		std::cout << "please enter a meaningful number to build or 0 to exit building menu." << std::endl;
		std::cout << "To display building menu, type a number over 9000." << std::endl;
		buildinginput=-1;
	} 
}


The timer std::thread is trying to get working:

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void Planet::BuildingTimer (BuildTimerStruct Starter)
{
	this->building[Starter.buildingid]=BUILDING;

	this->timeleft=Starter.TotalTime;
	int InitialTime=clock();
	while(Starter.timelefttimer>0)
	{
		this->timeleft=this->timeleft-(clock()-InitialTime)/CLOCKS_PER_SEC;
	}
	this->building[Starter.buildingid]=BUILT;

	if (DebugMode==true)
		std::cout << BLDGID(Starter.buildingid) <<" has been built on " << name << "." <<std::endl;
}


std::thread did not like functions taking in more than 1 argument, so I made a class (instead of a struct so I can use "delete this;") to pass on arguments. A few things need to be pointers to allow the separate thread/function to change variables as it works.

When I try to compile this program, it gives me this error:

Error 1 error C2064: term does not evaluate to a function taking 1 arguments c:\program files (x86)\microsoft visual studio 11.0\vc\include\functional 1152 1


which leads me to this:

_VARIADIC_EXPAND_0X(_CLASS_BIND, , , , )

I'm clueless on what's causing std::thread to fail.
Last edited on
cire (8284)
I'm clueless on what's causing std::thread to fail.


The member function Planet::BuildingTimer is not a function that takes 1 argument. All member functions that are not static take a hidden parameter (the this pointer,) so Planet::BuildingTimer actually takes two arguments.

With a little C experience and no C++ experience you have no chance of getting threading correct. Maybe you should begin with something a little easier to get your head around. Like, the basics of classes. There are quite a few flaws in your code that suggest that might be the way to go.
angus725 (2)
Inclusion of the "this" pointer fixed the problem. Thanks!

Could you highlight some of the other flaws in the code so I know what are potential problems?
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