连接通不过，请大神们帮忙看看
CPP文件：
/*----------------------------------------------------
SYSMETS2.C -- System Metrics Display Program No. 2
(c) Charles Petzold, 1998
----------------------------------------------------*/
#define WINVER 0x0500
#include <windows.h>
#include "sysmets.h"
LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ;
int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance,
PSTR szCmdLine, int iCmdShow)
{
static TCHAR szAppName[] = TEXT ("SysMets2") ;
HWND hwnd ;
MSG msg ;
WNDCLASS wndclass ;
wndclass.style = CS_HREDRAW | CS_VREDRAW ;
wndclass.lpfnWndProc = WndProc ;
wndclass.cbClsExtra = 0 ;
wndclass.cbWndExtra = 0 ;
wndclass.hInstance = hInstance ;
wndclass.hIcon = LoadIcon (NULL, IDI_APPLICATION) ;
wndclass.hCursor = LoadCursor (NULL, IDC_ARROW) ;
wndclass.hbrBackground = (HBRUSH) GetStockObject (WHITE_BRUSH) ;
wndclass.lpszMenuName = NULL ;
wndclass.lpszClassName = szAppName ;
if (!RegisterClass (&wndclass))
{
MessageBox (NULL, TEXT ("This program requires Windows NT!"),
szAppName, MB_ICONERROR) ;//属主窗口句柄，显示的文字，标题，窗口风格
return 0 ;
}
//WS_VSCROLL创建窗口带有垂直滚动条
hwnd = CreateWindow (szAppName, TEXT ("Get System Metrics No. 2"),
WS_OVERLAPPEDWINDOW | WS_VSCROLL,
CW_USEDEFAULT, CW_USEDEFAULT,
CW_USEDEFAULT, CW_USEDEFAULT,
NULL, NULL, hInstance, NULL) ;
ShowWindow (hwnd, iCmdShow) ;
UpdateWindow (hwnd) ;
while (GetMessage (&msg, NULL, 0, 0))
{
TranslateMessage (&msg) ;
DispatchMessage (&msg) ;
}
return msg.wParam ;
}
LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
static int cxChar, cxCaps, cyChar, cyClient, iVscrollPos ;
HDC hdc ;
int i, y ;
PAINTSTRUCT ps ;
TCHAR szBuffer[10] ;
TEXTMETRIC tm ;
switch (message)
{
case WM_CREATE:
hdc = GetDC (hwnd) ;
GetTextMetrics (hdc, &tm) ;
cxChar = tm.tmAveCharWidth ;
cxCaps = (tm.tmPitchAndFamily & 1 ? 3 : 2) * cxChar / 2 ;
cyChar = tm.tmHeight + tm.tmExternalLeading ;
ReleaseDC (hwnd, hdc) ;
SetScrollRange (hwnd, SB_VERT, 0, NUMLINES - 1, FALSE) ;//最后一个参数表示，滚动条是否重画以反映变化
SetScrollPos (hwnd, SB_VERT, iVscrollPos, TRUE) ;
return 0 ;
case WM_SIZE:
cyClient = HIWORD (lParam) ;//Iparam低位表示宽度，高位表示高度，消息结构体中的一个变量
return 0 ;
case WM_VSCROLL:
switch (LOWORD (wParam))//表示鼠标对滚动条的操作
{
case SB_LINEUP://滚动条上移一行
iVscrollPos -= 1 ;
break ;
case SB_LINEDOWN:
iVscrollPos += 1 ;
break ;
case SB_PAGEUP://滚动条上移一页
iVscrollPos -= cyClient / cyChar ;
break ;
case SB_PAGEDOWN:
iVscrollPos += cyClient / cyChar ;//用户区高度/单行高度，得到一页移动总行数
break ;
case SB_THUMBPOSITION:
iVscrollPos = HIWORD (wParam) ;//鼠标释放时滚动条位置
break ;
default :
break ;
}
iVscrollPos = max (0, min (iVscrollPos, NUMLINES - 1)) ;
if (iVscrollPos != GetScrollPos (hwnd, SB_VERT))//获得THUMB位置（未改变前）
{
SetScrollPos (hwnd, SB_VERT, iVscrollPos, TRUE) ;
InvalidateRect (hwnd, NULL, TRUE) ;//函数将产生WM_PAINT消息，NULL表示整个客户区被更新
//for(a = 0, b = 0; a < 1000000000; a++, b++){}//slow
}
return 0 ;
case WM_PAINT:
hdc = BeginPaint (hwnd, &ps) ;
//重画客户区
for (i = 0 ; i < NUMLINES ; i++)
{
y = cyChar * (i - iVscrollPos) ;//将滚动框所处位置，作为客户区重绘内容的第一行
TextOut (hdc, 0, y,
sysmetrics[i].szLabel,
lstrlen (sysmetrics[i].szLabel)) ;
TextOut (hdc, 22 * cxCaps, y,
sysmetrics[i].szDesc,
lstrlen (sysmetrics[i].szDesc)) ;
SetTextAlign (hdc, TA_RIGHT | TA_TOP) ;
TextOut (hdc, 22 * cxCaps + 40 * cxChar, y, szBuffer,
wsprintf (szBuffer, TEXT ("%5d"),
GetSystemMetrics (sysmetrics[i].iIndex))) ;//缓冲区，格式控制，输出内容，可以将数值转化为字符串，返回字符串长度，不包括'\'
SetTextAlign (hdc, TA_LEFT | TA_TOP) ;
}
EndPaint (hwnd, &ps) ;
return 0 ;
case WM_DESTROY:
PostQuitMessage (0) ;
return 0 ;
}
return DefWindowProc (hwnd, message, wParam, lParam) ;
}
编译能通过，但是连接时候总是报错：
LIBCD.lib(crt0.obj) : error LNK2001: unresolved external symbol _main
Debug/SYSMET2.exe : fatal error LNK1120: 1 unresolved externals
执行 link.exe 时出错.
[解决办法]
库文件没导入，看下配置路径对不对
