Win32 Static Variable link error [closed] - c++

Question

This question is unlikely to help any future visitors; it is only relevant to a small geographic area, a specific moment in time, or an extraordinarily narrow situation that is not generally applicable to the worldwide audience of the internet. For help making this question more broadly applicable, visit the help center.
Closed 10 years ago.
Why does this happen?
1>------ Build started: Project: Client, Configuration: Debug Win32 ------
1> WindowManager.cpp
1> Generating Code...
1> Compiling...
1> Main.cpp
1> Generating Code...
1>WindowManager.obj : error LNK2001: unresolved external symbol
"private: static int WindowManager::win_stat" (?win_stat#WindowManager##0HA)
1>C:\Users\user\documents\visual studio
2012\Projects\TalkToMe\Debug\Client.exe : fatal error LNK1120: 1 unresolved externals
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ==========
WindowManager.cpp
#include "WindowManager.h"
void WindowManager::PekMessage()
{
if(PeekMessage(&msg, window, 0, 0, PM_REMOVE))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
}
}
bool WindowManager::isWindowOpen()
{
return win_stat != -1;
}
HWND WindowManager::textbox(int width, int height, int xPos, int yPos, LPCSTR content, bool edit_able)
{
int type = (edit_able) ? (WS_CHILD|WS_VISIBLE|ES_AUTOHSCROLL) : (WS_CHILD|WS_VISIBLE|WS_HSCROLL|ES_AUTOHSCROLL);
return CreateWindowEx(
WS_EX_CLIENTEDGE,
"EDIT",
content,
type,
xPos,
yPos,
width,
height,
window,
(HMENU)50,
GetModuleHandle(NULL),
NULL
);
}
HWND WindowManager::textbox(Vector size, Vector position, LPCSTR content, bool edit_able)
{
return textbox(size.getX(), size.getY(), position.getX(), position.getY(), content, edit_able);
}
LRESULT CALLBACK WindowManager::WindowProcedure(HWND winhan,UINT uint_Message,WPARAM parameter1,LPARAM parameter2)
{
switch(uint_Message)
{
case 16: // exit button
win_stat = -1;
break;
}
return DefWindowProc(winhan,uint_Message,parameter1,parameter2);
}
WindowManager::WindowManager(LPCTSTR title,int x, int y, int width, int height)
{
WNDCLASSEX wnd;
wnd.cbSize = sizeof(wnd);
wnd.style = CS_HREDRAW | CS_VREDRAW;
wnd.lpfnWndProc = WindowProcedure;
wnd.cbClsExtra = 0;
wnd.cbWndExtra = 0;
wnd.hInstance = GetModuleHandle(NULL);
wnd.hIcon = NULL;
wnd.hCursor = LoadCursor(NULL,IDC_ARROW);
wnd.hbrBackground = GetSysColorBrush(NULL);
wnd.lpszClassName = "TalkToMe";
wnd.lpszMenuName = NULL;
wnd.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
RegisterClassEx(&wnd);
window = CreateWindowEx(WS_EX_CONTROLPARENT, wnd.lpszClassName, title,
WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU | WS_MINIMIZEBOX | WS_VISIBLE, x, y, width, height,NULL, NULL,
GetModuleHandle(NULL), NULL);
}
WindowManager::~WindowManager()
{
DestroyWindow(window);
}
WindowManager.h
#pragma once
#pragma comment(linker,"\"/manifestdependency:type='win32' name='Microsoft.Windows.Common-Controls' version='6.0.0.0' processorArchitecture='*' publicKeyToken='6595b64144ccf1df' language='*'\"")
#include <Windows.h>
#include "Vector.h"
class WindowManager
{
private:
MSG msg;
HWND window;
static int win_stat;
public:
WindowManager(LPCTSTR title,int x, int y, int width, int height);
~WindowManager();
static LRESULT CALLBACK WindowProcedure(HWND winhan,UINT uint_Message,WPARAM parameter1,LPARAM parameter2);
HWND textbox(int width, int height, int xPos, int yPos, LPCSTR content, bool edit_able=true);
HWND textbox(Vector size, Vector position, LPCSTR content, bool edit_able=true);
bool isWindowOpen();
void PekMessage();
};

Answer 1

The part in the header
static int win_stat;
is only a declaration. You also have to add
int WindowManager::win_stat;
to the .cpp file, just like you define the member functions there.