Arreter le fonctionnement d'un bouton (boucle while )

#include <windows.h>
#include <stdint.h>
#include <stdio.h>
#include <tchar.h>
#include <setupapi.h>
#include <locale.h>


#define ID_B_START 0
#define ID_B_Stop 1
#define ID_B_Exit 2

HINSTANCE instance;

LRESULT CALLBACK procedureFenetrePrincipale(HWND, UINT, WPARAM, LPARAM);
void Communication (HANDLE hCom,  DCB dcb);/*fonction qui ouvre le port ensuite lance une lecture dans une boucle while */
void Fermeture (HANDLE hCom,  DCB dcb);


int WinMain (HINSTANCE cetteInstance, HINSTANCE precedenteInstance, LPSTR lignesDeCommande, int modeDAffichage)
{
    HWND fenetrePrincipale;
    MSG message;
    WNDCLASS classeFenetre;
    HMENU menu;

    instance = cetteInstance;

    menu = CreateMenu();
    AppendMenu(menu, MF_POPUP, (UINT)sousMenu, L"File");
	
	

    classeFenetre.style = 0;
    classeFenetre.lpfnWndProc = procedureFenetrePrincipale; //fct callback
    classeFenetre.cbClsExtra = 0;
    classeFenetre.cbWndExtra = 0;

    classeFenetre.hInstance = NULL;
    classeFenetre.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    classeFenetre.hCursor = LoadCursor(NULL, IDC_ARROW);
    classeFenetre.hbrBackground = (HBRUSH)(1 + COLOR_BTNFACE);
    classeFenetre.lpszMenuName = NULL;
    classeFenetre.lpszClassName = L"classeF";

    // On prévoit quand même le cas où ça échoue
    if(!RegisterClass(&classeFenetre))
		return FALSE;

    fenetrePrincipale = CreateWindow(
		L"classeF", 
		L"Interface STPM34 !",
		WS_OVERLAPPEDWINDOW, 
		CW_USEDEFAULT,
		CW_USEDEFAULT, 
		400, 
		400, 
		NULL,
		menu /* NULL si on n'a pas de menu sinon le non du menu Ou LoadMenu(instance, "ID_MENU")*/ , 
		cetteInstance, 
		NULL);
    
    if (!fenetrePrincipale) 
		return FALSE;

    ShowWindow(fenetrePrincipale, modeDAffichage);
    UpdateWindow(fenetrePrincipale);


    while (GetMessage(&message, NULL, 0, 0))
    {
        TranslateMessage(&message);
        DispatchMessage(&message);
    }
    return message.wParam;
}

LRESULT CALLBACK procedureFenetrePrincipale(HWND fenetrePrincipale, UINT message, WPARAM wParam, LPARAM lParam)
{
        static HWND bouton0 = {NULL};
	static HWND bouton1 = {NULL};
	static HWND bouton2 = {NULL};
	static DCB dcb;
       static HANDLE hCom;
	

    switch (message)
    {
        case WM_CREATE:
                   bouton0= CreateWindow(
					L"BUTTON",
					L"Start", 
					WS_CHILD | WS_VISIBLE,
					5,
					125,
					383,
					30,
					fenetrePrincipale, 
					(HMENU)ID_B_START,
					instance,
					NULL);

		bouton1 = CreateWindow(
					L"BUTTON", 
					L"Stop", 
					WS_CHILD | WS_VISIBLE,
					5,
					165,
					383, 
					30,
					fenetrePrincipale,
					(HMENU)ID_B_Stop,
					instance, 
					NULL);

                bouton2 = CreateWindow(
					L"BUTTON", 
					L"Exit", 
					WS_CHILD | WS_VISIBLE,
					5,
					205,
					383, 
					30,
					fenetrePrincipale,
					(HMENU)ID_B_Exit,
					instance, 
					NULL);
            return 0;

        case WM_COMMAND:
            switch(LOWORD(wParam))
            {
									 

		case ID_B_START:
					
			Communication (hCom,   dcb);
			break;
		case ID_B_Stop: /*Je veux dés que j'appuie sur ce bouton la commuincation s'arrete */
			Fermeture ( hCom, dcb);
                        break;
                case ID_B_Exit:
                     SendMessage(fenetrePrincipale, WM_DESTROY, 0, 0);
                     break;
            }
            return 0;

        case WM_DESTROY:
            PostQuitMessage(0);
            return 0;

        default:
            return DefWindowProc(fenetrePrincipale, message, wParam, lParam);
    }
}