C에서 C++ 코드 호출

출처: http://yesarang.tistory.com/69

//	thread.c
#include <stdio.h>
#include <pthread.h>
#include <unistd.h>	//	for sleep()
#include <stdlib.h>	//	for free()

void* start_routine(void* data)
{
	int	i	=	0;
	printf("starts to run\n");
	while ( ++i < 20 )	{
		printf("%d\n", i);
		sleep(1);
	}

	if ( data != NULL )
		free(data);

	return	NULL;
}

int main(void)
{
	pthread_t	thrd;
	int	nr	=	0;
	void*	data;

	//	created thread executes start_routine
	nr	=	pthread_create(&thrd, NULL, start_routine, NULL);
	//	program will be splitted to 2 threads
	nr	=	pthread_join(thrd, &data);
	if ( data != NULL )
		free(data);

	return	0;
}

/*
$ gcc -o thread thread.c -lpthread
$ ./thread 
starts to run
1
2
...
18
19
*/

//	c2cpp.h
#ifndef	_C2CPP_H
#define _C2CPP_H

#include <iostream>
#include <unistd.h>

using namespace std;

class UsefulCppClass	{
public:
	UsefulCppClass(string name): _name(name) {}

	void DoSomeAction()	{
		cout << _name << ": I'm doing some useful job. step #1" << endl;
		sleep(1);
		cout << _name << ": I'm doing some useful job. step #2" << endl;
		sleep(1);
		cout << _name << ": I'm doing some useful job. step #3" << endl;
		sleep(1);
		cout << _name << ": I'm doing some useful job. step #4" << endl;
		sleep(1);
		cout << _name << ": I'm doing some useful job. step #5" << endl;
		sleep(1);
		cout << _name << ": Exiting..." << endl;
		sleep(1);
	}

private:
	string _name;
};

#endif	//	_C2CPP_H

//	c2cpp.cpp
#include "c2cpp.h"

int main()
{
	pthread_t	thrd;
	int	nr;
	UsefulCppClass*	pInst	=	new UsefulCppClass("01");
	void*	pData;

	nr	=	pthread_create(&thrd, NULL, &UsefulCppClass::DoSomeAction, NULL);
	pthread_join(thrd, &pData);

	return	0;
}

/*
$ g++ -o c2cpp c2cpp.cpp -lpthread
In file included from c2cpp.cpp:1:
c2cpp.cpp: In function ‘int main()’:
c2cpp.cpp:10: error: cannot convert ‘void (UsefulCppClass::*)()’ to ‘void* (*)(void*)’ for
argument ‘3’ to ‘int pthread_create(pthread_t*, const pthread_attr_t*,
void* (*)(void*), void*)’
*/

//	c2cpp.h
//	same as above

//	c2cpp.cpp
#include "c2cpp.h"

void* UsefulCppClassWrappingFunction(void* pInst)
{
	cout << "UsefulCppClassWrappingFunction() called" << endl;
	//	type casting to UsefulCppClass instance
	UsefulCppClass*	pInstance	=	static_cast<UsefulCppClass*>(pInst);
	//	call method
	pInstance->DoSomeAction();
}

int main()
{
	pthread_t	thrd;
	int	nr;
	UsefulCppClass*	pInst	=	new UsefulCppClass("01");
	void*	pData;

	nr	=	pthread_create(&thrd, NULL, &UsefulCppClassWrappingFunction, NULL);
	pthread_join(thrd, &pData);

	return	0;
}

/*
$ g++ -o c2cpp c2cpp.cpp -lpthread -g
$ ./c2cpp 
UsefulCppClassWrappingFunction() called
01: I'm doing some useful job. step #1
01: I'm doing some useful job. step #2
01: I'm doing some useful job. step #3
01: I'm doing some useful job. step #4
01: I'm doing some useful job. step #5
01: Exiting...
*/

//	c2cpp.h
//	same as above

//	c2cpp.cpp
#include "c2cpp.h"

class UsefulCppClassWrapper	{
public:
	static void* DoIt(void* pInst)	{
		cout << "UsefulCppClassWrapper::DoIt() called" << endl;
		UsefulCppClass*	pInstance	=	static_cast<UsefulCppClass*>(pInst);
		pInstance->DoSomeAction();

		return	NULL;
	}
};

int main()
{
	pthread_t	thrd;
	int	nr;
	UsefulCppClass*	pInst	=	new UsefulCppClass("01");
	void*	pData;

	nr	=	pthread_create(&thrd, NULL, &UsefulCppClassWrapper::DoIt, pInst);
	pthread_join(thrd, &pData);

	return	0;
}