我试图在类中创建一个线程，但是我收到了一个错误。我只是想知道是否有办法解决这个问题，还是只能在int main()内使用线程？
C:\windows_thread_2\windows_thread_2.cpp||In member function 'void windows_thread::thread()':|
C:\windows_thread_2\windows_thread_2.cpp|24|error: argument of type 'DWORD (windows_thread::)(void*)' does not match 'DWORD (*)(void*)'|
C:\windows_thread_2\windows_thread_2.cpp||In member function 'DWORD windows_thread::Thread_no_1(void*)':|
C:\windows_thread_2\windows_thread_2.cpp|70|warning: deprecated conversion from string constant to 'char*'|
||=== Build finished: 1 errors, 1 warnings ===|
继承人的代码。
#include <windows.h>
//#include <strsafe.h>
#include <stdio.h>
#define BUF_SIZE 255
class windows_thread
{
//-------------------------------------------------------------------
// A function to Display the message indicating in which tread we are
//-------------------------------------------------------------------
public:
windows_thread(){}
~windows_thread(){}
void thread()
{
int Data_Of_Thread_1 = 1; // Data of Thread 1
HANDLE Handle_Of_Thread_1 = 0; // variable to hold handle of Thread 1
HANDLE Array_Of_Thread_Handles[1]; // Aray to store thread handles
// Create thread 1.
Handle_Of_Thread_1 = CreateThread( NULL, 0, Thread_no_1, &Data_Of_Thread_1, 0, NULL);
if ( Handle_Of_Thread_1 == NULL) ExitProcess(Data_Of_Thread_1);
// Store Thread handles in Array of Thread Handles as per the requirement of WaitForMultipleObjects()
Array_Of_Thread_Handles[0] = Handle_Of_Thread_1;
// Wait until all threads have terminated.
WaitForMultipleObjects( 1, Array_Of_Thread_Handles, TRUE, INFINITE);
printf("Since All threads executed lets close their handles \n");
// Close all thread handles upon completion.
CloseHandle(Handle_Of_Thread_1);
}
void DisplayMessage (HANDLE hScreen, char *ThreadName, int Data, int Count)
{
TCHAR msgBuf[BUF_SIZE];
size_t cchStringSize;
DWORD dwChars;
// Print message using thread-safe functions.
//StringCchPrintf(msgBuf, BUF_SIZE, TEXT("Executing iteration %02d of %s having data = %02d \n"), Count, ThreadName, Data);
//StringCchLength(msgBuf, BUF_SIZE, &cchStringSize);
WriteConsole(hScreen, msgBuf, cchStringSize, &dwChars, NULL);
Sleep(1000);
}
//-------------------------------------------
// A function that represents Thread number 1
//-------------------------------------------
DWORD WINAPI Thread_no_1( LPVOID lpParam )
{
int Data = 0;
int count = 0;
HANDLE hStdout = NULL;
// Get Handle To screen. Else how will we print?
if( (hStdout = GetStdHandle(STD_OUTPUT_HANDLE)) == INVALID_HANDLE_VALUE )
return 1;
// Cast the parameter to the correct data type passed by callee i.e main() in our case.
Data = *((int*)lpParam);
for (count = 0; count <= 4; count++ )
{
DisplayMessage (hStdout, "Thread_no_1", Data, count);
}
return 0;
}
};
int main()
{
windows_thread threading;
threading.thread();
return 0;
}
我根据答案编辑了代码，如果可以解决此错误，请编辑它。
line 78 error: no matching function for call to 'windows_thread::Thread_no_1()'|
#include <windows.h>
//#include <strsafe.h>
#include <stdio.h>
#define BUF_SIZE 255
class windows_thread
{
//-------------------------------------------------------------------
// A function to Display the message indicating in which tread we are
//-------------------------------------------------------------------
public:
windows_thread(){}
~windows_thread(){}
void thread()
{
int Data_Of_Thread_1 = 1; // Data of Thread 1
HANDLE Handle_Of_Thread_1 = 0; // variable to hold handle of Thread 1
HANDLE Array_Of_Thread_Handles[1]; // Aray to store thread handles
// Create thread 1.
Handle_Of_Thread_1 = CreateThread( NULL, 0, Wrap_Thread_no_1, &Data_Of_Thread_1, 0, NULL);
if ( Handle_Of_Thread_1 == NULL) ExitProcess(Data_Of_Thread_1);
// Store Thread handles in Array of Thread Handles as per the requirement of WaitForMultipleObjects()
Array_Of_Thread_Handles[0] = Handle_Of_Thread_1;
// Wait until all threads have terminated.
WaitForMultipleObjects( 1, Array_Of_Thread_Handles, TRUE, INFINITE);
printf("Since All threads executed lets close their handles \n");
// Close all thread handles upon completion.
CloseHandle(Handle_Of_Thread_1);
}
void DisplayMessage (HANDLE hScreen, char *ThreadName, int Data, int Count)
{
TCHAR msgBuf[BUF_SIZE];
size_t cchStringSize;
DWORD dwChars;
// Print message using thread-safe functions.
//StringCchPrintf(msgBuf, BUF_SIZE, TEXT("Executing iteration %02d of %s having data = %02d \n"), Count, ThreadName, Data);
//StringCchLength(msgBuf, BUF_SIZE, &cchStringSize);
WriteConsole(hScreen, msgBuf, cchStringSize, &dwChars, NULL);
Sleep(1000);
}
//-------------------------------------------
// A function that represents Thread number 1
//-------------------------------------------
DWORD WINAPI Thread_no_1( LPVOID lpParam )
{
int Data = 0;
int count = 0;
HANDLE hStdout = NULL;
// Get Handle To screen. Else how will we print?
if( (hStdout = GetStdHandle(STD_OUTPUT_HANDLE)) == INVALID_HANDLE_VALUE )
return 1;
// Cast the parameter to the correct data type passed by callee i.e main() in our case.
Data = *((int*)lpParam);
for (count = 0; count <= 1; count++ )
{
//DisplayMessage (hStdout, "Thread_no_1", Data, count);
}
return 0;
}
static DWORD WINAPI Wrap_Thread_no_1( LPVOID lpParam )
{
windows_thread *self = reinterpret_cast<windows_thread*>(lpParam);
self->Thread_no_1();
}
};
int main()
{
windows_thread threading;
threading.thread();
return 0;
}
答案 0 :(得分：4)
线程必须是“普通函数”，而不是对类的非静态成员函数的调用 - 这些需要“this-pointer”的额外“隐藏”参数。
由于到目前为止您的代码没有使用任何成员变量[据我所知]，简单的解决方案是创建函数static。
如果你想使用你的类的成员变量或成员函数，那么你需要有一个静态函数并将对象（this）作为参数传递给线程（然后），然后使用reinterpret_cast<windows_thread*>(arg);将其转换回来。
这些方面的东西：
...
Handle_Of_Thread_1 = CreateThread( NULL, 0, Wrap_Thread_no_1, this, 0, NULL);
...
static DWORD WINAPI Wrap_Thread_no_1( LPVOID lpParam )
{
windows_thread *self = reinterpret_cast<windows_thread*>(lpParam);
self->Thread_no_1();
}
我删除了原来的论点。假设线程每个对象只运行一个线程，则可以使其成为成员变量。如果您需要具有单个参数的多个线程，则需要将传入的参数设为struct或class，并reinterpret_cast为该参数，并将this指针存储为部分struct或class [然后可以windows_thread*，因此不需要投射]。
答案 1 :(得分：3)
您正在尝试将pointer-to-member传递给线程，该线程与此处的原始指针不同。它需要一个物体附在它上面。
Handle_Of_Thread_1 = CreateThread( NULL, 0, Thread_no_1, &Data_Of_Thread_1, 0, NULL);
通过更改此项来创建函数static：
DWORD WINAPI Thread_no_1( LPVOID lpParam )
对此：
static DWORD WINAPI Thread_no_1( LPVOID lpParam )
...表明（正确地）该函数不需要this。