我搜索了一个答案但却找不到答案。我在线程上工作。我有一个线程类和它的3个子类。当我调用这3个子类中的一个时，我必须在线程类中创建一个线程并使用它们的main（因为线程main是纯虚拟抽象）但问题是在它调用它调用的Create Thread函数（c'tor of thread）之前那些分管。
thread.h
#ifndef _THREAD_H_
#define _THREAD_H_
#include <string>
#include <Windows.h>
#include <iosfwd>
#include "Mutex.h"
#include "SynchronizedArray.h"
#include "SynchronizedCounter.h"
std::string message = "";
class Thread{
private:
HANDLE hThread;
int idThread;
protected:
SynchronizedArray *arr;
int size;
SynchronizedCounter *counter;
public:
Thread(DWORD funct){ //creates a thread by calling subclasses main functions appropriately
hThread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE) funct, NULL, 0, (LPDWORD)&idThread);
}
virtual DWORD WINAPI main(void*) = 0; // pure virtual abstract class
void suspend(){ //suspent the thread
SuspendThread(hThread);
}
void resume(){// retume the thread
ResumeThread(hThread);
}
void terminate(){ // terminates the thread
TerminateThread(hThread,0);
}
void join(){ // joins the thread
Mutex mut;
mut.lock();
}
static void sleep(int sec){ //wrapper of sleep by sec
Sleep(sec*1000);
}
};
#endif
作为示例的3个继承的Thread类中的1个（所有这些都是相同的）
PrintThread.h
#ifndef _PRINTINGTHREAD_H_
#define _PRINTINGTHREAD_H_
#include "SynchronizedArray.h"
#include "SynchronizedCounter.h"
#include "Thread.h"
#include <iostream>
#include "SortingThread.h"
#include "CountingThread.h"
#include <string>
#include <Windows.h>
extern CountingThread counterThread1;
extern CountingThread counterThread2;
extern SortingThread sortingThread1;
extern SortingThread sortingThread2;
class PrintingThread:public Thread{
private:
char temp;
public:
PrintingThread() :Thread(main(&temp)){
}
DWORD WINAPI main(void* param)
{
std::cout << "Please enter an operation ('showcounter1','showcounter2','showarray1','showarray2' or 'quit')" << std::endl;
std::cin >> message;
while (message != "quit")
{
if (message == "showcounter1")
{
std::cout << counterThread1<<std::endl;
}
else if (message == "showcounter2")
{
std::cout << counterThread2 << std::endl;
}
else if (message == "showarray1")
{
std::cout << sortingThread1 << std::endl;
}
else if (message == "showarray2")
{
std::cout << sortingThread2 << std::endl;
}
else {
std::cout << "Invalid operation";
}
std::cout << "Please enter an operation ('show counter 1','show counter 2','show array 1','show array 2' or 'quit')" << std::endl;
std::cin >> message;
}
return 0;
}
};
#endif
为什么它在调用线程的c'tor之前调用主线。
答案 0 :(得分：2)
您的PrintingThread构造函数初始值设定项列表实际上是调用 PrintingThread::main并将结果传递给Thread构造函数。这意味着CreateThread调用正在接收DWORD（在本例中为0）作为其函数参数。
您需要更改类设计以实际传递函数指针和上下文参数，例如：
Thread(DWORD funct){
hThread = CreateThread(NULL, 0, (LPTHREAD_START_ROUTINE) funct, NULL, 0, (LPDWORD)&idThread);
应该是：
Thread(LPTHREAD_START_ROUTINE funct, LPVOID arg) {
hThread = CreateThread(NULL, 0, funct, arg, 0, (LPDWORD)&idThread);
（你必须施放funct的事实应该是一个巨大的红旗。）
同样，子类构造函数将从：
更改PrintingThread() :Thread(main(&temp)){
为：
PrintingThread(): Thread(main, &temp) {
请注意，您的代码仍会有其他问题，例如线程函数应该是静态的（因此您无法尝试访问成员函数）。
答案 1 :(得分：2)
你需要做更像这样的事情：
thread.h：
#ifndef _THREAD_H_
#define _THREAD_H_
#include <string>
#include <Windows.h>
#include <iosfwd>
#include "Mutex.h"
#include "SynchronizedArray.h"
#include "SynchronizedCounter.h"
class Thread
{
private:
HANDLE hThread;
DWORD idThread;
void *pParam;
static DWORD WINAPI ThreadProc(LPVOID lpParameter)
{
Thread *pThis = (Thread*) lpParameter;
return pThis->main(pThis->pParam);
}
protected:
SynchronizedArray *arr;
int size;
SynchronizedCounter *counter;
public:
Thread(void *aParam)
{
//creates a thread by calling subclasses main functions appropriately
pParam = aParam;
hThread = CreateThread(NULL, 0, &ThreadProc, this, 0, &idThread);
}
virtual DWORD main(void*) = 0; // pure virtual abstract class
void suspend()
{
//suspent the thread
SuspendThread(hThread);
}
void resume()
{
// resume the thread
ResumeThread(hThread);
}
void terminate()
{
// terminates the thread
TerminateThread(hThread, 0);
}
void join()
{
// joins the thread
Mutex mut;
mut.lock();
}
static void sleep(int sec)
{
//wrapper of sleep by sec
Sleep(sec*1000);
}
};
#endif
PrintThread.h：
include <iostream>
#include "SortingThread.h"
#include "CountingThread.h"
#include <string>
#include <Windows.h>
extern CountingThread counterThread1;
extern CountingThread counterThread2;
extern SortingThread sortingThread1;
extern SortingThread sortingThread2;
class PrintingThread : public Thread
{
private:
char temp;
public:
PrintingThread() : Thread(&temp)
{
}
virtual DWORD main(void* param)
{
std::string message;
do
{
std::cout << "Please enter an operation ('showcounter1','showcounter2','showarray1','showarray2' or 'quit')" << std::endl;
std::cin >> message;
if (message == "quit")
{
break;
}
if (message == "showcounter1")
{
std::cout << counterThread1 << std::endl;
}
else if (message == "showcounter2")
{
std::cout << counterThread2 << std::endl;
}
else if (message == "showarray1")
{
std::cout << sortingThread1 << std::endl;
}
else if (message == "showarray2")
{
std::cout << sortingThread2 << std::endl;
}
else
{
std::cout << "Invalid operation";
}
}
while (true);
return 0;
}
};
#endif