Thread: Too much Cpu usage

I cant seem to find why it uses 50% of the CPU.
Apparently im not getting the handle of the Win_1 because its writing over the window and not in it.

Thanks for any suggestion!

Code:

#include <windows.h>
#include <tchar.h>
#include <string>
#include <iostream>
#include <richedit.h>
#pragma comment(lib,"user32.lib")
#pragma comment(lib,"Gdi32.lib")
using namespace std;

#define IDB_TEXT2 101
#define IDB_TEXT3 102
#define GetF 103

HWND hwnd, Win_1, Win_2, Send;
MSG Msg;
HDC hdc;
PAINTSTRUCT ps;

TCHAR *buf;
int length;
size_t found ;
string Text, str;

void GetIt()
{
     hdc = BeginPaint(Win_1, &ps);
     length = GetWindowTextLength(Win_2);
     buf = new TCHAR[length+1];
     GetWindowText(GetDlgItem(hwnd,IDB_TEXT3), buf, length+1);
     str   = buf;
     found = str.find("\r\n");
     Text  = str.substr(0,found);
     TextOut(hdc, 10, 10, Text.c_str(), strlen(Text.c_str()));
     EndPaint(Win_1, &ps);
     delete[] buf;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam){
  switch(msg){
              case WM_CREATE:
                   Win_1 = CreateWindowEx(0,"Edit","",
                         WS_VISIBLE | WS_CHILD |  WS_HSCROLL | WS_VSCROLL |
                         ES_AUTOHSCROLL | ES_WANTRETURN | ES_MULTILINE,
                         20, 20, 550, 460,hwnd,(HMENU) IDB_TEXT2,
                         ((LPCREATESTRUCT)lParam)->hInstance,NULL);
                   Win_2 = CreateWindowEx(0,"Edit","hello",
                         WS_VISIBLE | WS_CHILD |  WS_HSCROLL | WS_VSCROLL |
                         ES_AUTOHSCROLL | ES_WANTRETURN | ES_MULTILINE,
                         20, 500, 550, 180,hwnd,(HMENU) IDB_TEXT3,
                         ((LPCREATESTRUCT)lParam)->hInstance,NULL);
                   Send = CreateWindowEx(0,"Button","Send",
                         WS_CHILD | WS_VISIBLE | WS_BORDER,
                         20, 700, 550, 20,hwnd,(HMENU)GetF,0,NULL);

                   EnableWindow(Send ,TRUE);
                   break;
              case WM_PAINT:
                   GetIt();
                   break;
              case WM_COMMAND:
                   switch(wParam)
                   {
                    case GetF:
                         InvalidateRect(hwnd,0,FALSE);
                         break;
                   }
              case WM_TIMER:
                   break;

              case WM_CLOSE:
                   DestroyWindow(hwnd);
                   break;

              case WM_DESTROY:
                   PostQuitMessage(0);
                   break;
              default:
                   return DefWindowProc(hwnd,msg,wParam,lParam);
       }
       return 0;
}

int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,LPSTR lpCmdLine,int nCmdShow)
{
    WNDCLASSEX wc;
    wc.hInstance = hInstance;
    wc.cbClsExtra = 0;
    wc.cbSize = sizeof(WNDCLASSEX);
    wc.cbWndExtra = 0;
    wc.hbrBackground = (HBRUSH) CreateSolidBrush(RGB(100,100,100));
    wc.hCursor = LoadCursor(NULL,IDC_ARROW);
    wc.hIcon   = LoadIcon (NULL, IDI_APPLICATION) ;
    wc.lpfnWndProc =  WndProc;
    wc.lpszClassName = "Class";
    wc.lpszMenuName = NULL;
    wc.style = 0;
    wc.hIconSm = NULL;
    if(!RegisterClassEx(&wc))
    {
        MessageBox(NULL, "Window Registration Failed!", "Error!",
        MB_ICONEXCLAMATION | MB_OK);
        return 0;
    }

    hwnd = CreateWindowEx(WS_EX_LEFT|WS_EX_LTRREADING|WS_EX_WINDOWEDGE,
                           "Class",
                           " The_Chatter",
                           WS_OVERLAPPEDWINDOW,
                           CW_USEDEFAULT, CW_USEDEFAULT, 600, 800,
                           HWND_DESKTOP, NULL, hInstance, NULL);

    if(hwnd == NULL)
    {
        MessageBox(NULL, "Window Creation Failed!", "Error!", MB_ICONEXCLAMATION | MB_OK); return 0;
    }

    SetTimer(hwnd,1,125,NULL);
    ShowWindow(hwnd, nCmdShow);
    UpdateWindow(hwnd);

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

BeginPain will cause the window to redraw, thus sending another WM_PAINT message.
To quote MSDN:
"An application should not call BeginPaint except in response to a WM_PAINT message."

Thank you Elysia but i got another program with BeginPaint and it wont use any CPU.

But on second thought maybe i should use SendMessage() instead of TextOut().

I tried it with SendMessage() but its not working either and still uses a lot of CPU.

Code:

#include <windows.h>
#include <tchar.h>
#include <string>
#include <iostream>
#include <richedit.h>
#pragma comment(lib,"user32.lib")
#pragma comment(lib,"Gdi32.lib")
using namespace std;

#define IDB_TEXT2 101
#define IDB_TEXT3 102
#define GetF 103

HWND hwnd, Win_1, Win_2, Send;
MSG Msg;
HDC hdc;
PAINTSTRUCT ps;

TCHAR *buf;
int length;
size_t found ;
string Text, str;

void GetIt()
{
     length = GetWindowTextLength(Win_2);
     buf = new TCHAR[length+1];
     GetWindowText(GetDlgItem(hwnd,IDB_TEXT3), buf, length+1);
     str   = buf;
     found = str.find("\r\n");
     Text  = str.substr(0,found);
     SendMessage(Win_1, LB_INSERTSTRING, (WPARAM)-1, (LPARAM)Text.c_str());/*
     hdc = BeginPaint(Win_1, &ps);
     TextOut(hdc, 10, 10, Text.c_str(), strlen(Text.c_str()));
     EndPaint(Win_1, &ps);*/
     delete[] buf;
}

LRESULT CALLBACK WndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam){
  switch(msg){
              case WM_CREATE:
                   Win_1 = CreateWindowEx(0,"Edit","",
                         WS_VISIBLE | WS_CHILD |  WS_HSCROLL | WS_VSCROLL |
                         ES_AUTOHSCROLL | ES_WANTRETURN | ES_MULTILINE,
                         20, 20, 550, 460,hwnd,(HMENU) IDB_TEXT2,
                         ((LPCREATESTRUCT)lParam)->hInstance,NULL);
                   Win_2 = CreateWindowEx(0,"Edit","hello",
                         WS_VISIBLE | WS_CHILD |  WS_HSCROLL | WS_VSCROLL |
                         ES_AUTOHSCROLL | ES_WANTRETURN | ES_MULTILINE,
                         20, 500, 550, 180,hwnd,(HMENU) IDB_TEXT3,
                         ((LPCREATESTRUCT)lParam)->hInstance,NULL);
                   Send = CreateWindowEx(0,"Button","Send",
                         WS_CHILD | WS_VISIBLE | WS_BORDER,
                         20, 700, 550, 20,hwnd,(HMENU)GetF,0,NULL);

                   EnableWindow(Send ,TRUE);
                   break;
              case WM_PAINT:
                   GetIt()
                   break;
              case WM_COMMAND:
                   switch(wParam)
                   {
                    case GetF:
                         //GetIt(hwnd);
                         InvalidateRect(Win_1,0,FALSE);
                         //system("start http://www.google.com");
                         break;
                   }
              case WM_TIMER:
                  // if (GetAsyncKeyState(VK_F11)) ShowWindow(hwnd,SW_HIDE);
                   //if (GetAsyncKeyState(VK_F12)) ShowWindow(hwnd,SW_SHOW);
                   break;

              case WM_CLOSE:
                   DestroyWindow(hwnd);
                   break;

              case WM_DESTROY:
                   PostQuitMessage(0);
                   break;
              default:
                   return DefWindowProc(hwnd,msg,wParam,lParam);
       }
       return 0;
}

I am really bad at Windows stuff, but I would encourage you to use a profiler to see the bottleneck. There are free ones out there, such as AMD's CodeAnalyst.

Thanks, ill check it out.

Thank you very much Bob!

Problem solved, lesson learned!

Originally Posted by Elysia

BeginPain will cause the window to redraw, thus sending another WM_PAINT message.
To quote MSDN:
"An application should not call BeginPaint except in response to a WM_PAINT message."

BeginPaint() does not send any msgs. The values returned are not valid in any other msg than WM_PAINT.

The issue appears to be using a function pointer to the paint handler (rather than an ID number) when creating the 'Send' control (and a timer firing every 125 ms).

I misinterpreted MSDN then...