Create the C-Language Source File

The C-language source file contains the WinMain function, the MainWndProc window function, the About dialog function, and the InitApplication and InitInstance initialization functions. Name the file GENERIC.C.

The contents of the file GENERIC.C look like this:

/***********************************************************************

PROGRAM: GENERIC.C

PURPOSE: Generic template for Windows applications

FUNCTIONS:

WinMain() - calls initialization function, processes message loop

InitApplication() - initializes window data and registers window

InitInstance() - saves instance handle and creates main window

MainWndProc() - processes messages

About() - processes messages for “About” dialog box

COMMENTS:

Windows can have several copies of your application running

at the same time. The variable hInst keeps track of which

instance this application is so that processing will be to

the correct window.

/****************************************************************************/

#include “windows.h” /* required for all Windows applications */

#include “generic.h” /* specific to this program */

HANDLE hInst; /* current instance */

/************************************************************************

FUNCTION: WinMain(HANDLE, HANDLE, LPSTR, int)

PURPOSE: calls initialization function, processes message loop

COMMENTS:

Windows recognizes this function by name as the initial entry point

for the program. This function calls the application initialization

routine, if no other instance of the program is running, and always

calls the instance initialization routine. It then executes a message

retrieval and dispatch loop that is the top-level control structure

for the remainder of execution. The loop is terminated when a WM_QUIT

message is received, at which time this function exits the application

instance by returning the value passed by PostQuitMessage().

If this function must abort before entering the message loop, it

returns the conventional value NULL.

**************************************************************************/

int PASCAL WinMain(hInstance, hPrevInstance, lpCmdLine, nCmdShow)

HANDLE hInstance; /* current instance */

HANDLE hPrevInstance; /* previous instance */

LPSTR lpCmdLine; /* command line */

int nCmdShow; /* show-window type (open/icon) */

{

MSG msg; /* message */

if (!hPrevInstance) /* Other instances of app running? */

if (!InitApplication(hInstance)) /* Initialize shared things */

return (FALSE); /* Exits if unable to initialize */

/* Perform initializations that apply to a specific instance */

if (!InitInstance(hInstance, nCmdShow))

return (FALSE);

/* Acquire and dispatch messages until a WM_QUIT message is received. */

while (GetMessage(&msg, /* message structure */

NULL, /* handle of window receiving the message */

NULL, /* lowest message to examine */

NULL)) /* highest message to examine */

{

TranslateMessage(&msg); /* Translates virtual key codes */

DispatchMessage(&msg); /* Dispatches message to window */

}

return (msg.wParam); /* Returns the value from PostQuitMessage */

}

/****************************************************************************

FUNCTION: InitApplication(HANDLE)

PURPOSE: Initializes window data and registers window class

COMMENTS:

This function is called at initialization time only if no other

instances of the application are running. This function performs

initialization tasks that can be done once for any number of running

instances.

In this case, we initialize a window class by filling out a data

structure of type WNDCLASS and calling the Windows RegisterClass()

function. Since all instances of this application use the same window

class, we only need to do this when the first instance is initialized.

****************************************************************************/

BOOL InitApplication(hInstance)

HANDLE hInstance; /* current instance */

{

WNDCLASS wc;

/* Fill in window class structure with parameters that describe the */

/* main window. */

wc.style = NULL; /* Class style(s). */

wc.lpfnWndProc = MainWndProc; /* Function to retrieve messages for */

/* windows of this class. */

wc.cbClsExtra = 0; /* No per-class extra data. */

wc.cbWndExtra = 0; /* No per-window extra data. */

wc.hInstance = hInstance; /* Application that owns the class. */

wc.hIcon = LoadIcon(NULL, IDI_APPLICATION);

wc.hCursor = LoadCursor(NULL, IDC_ARROW);

wc.hbrBackground = GetStockObject(WHITE_BRUSH);

wc.lpszMenuName = “GenericMenu”; /* Name of menu resource in .RC file. */

wc.lpszClassName = “GenericWClass”;/* Name used in call to CreateWindow. */

/* Register the window class and return success/failure code. */

return (RegisterClass(&wc));

}

/****************************************************************************

FUNCTION: InitInstance(HANDLE, int)

PURPOSE: Saves instance handle and creates main window

COMMENTS:

This function is called at initialization time for every instance of

this application. This function performs initialization tasks that

cannot be shared by multiple instances.

In this case, we save the instance handle in a static variable and

create and display the main program window.

****************************************************************************/

BOOL InitInstance(hInstance, nCmdShow)

HANDLE hInstance; /* Current instance identifier. */

int nCmdShow; /* Param for first ShowWindow() call. */

{

HWND hWnd; /* Main window handle. */

/* Save the instance handle in static variable, which will be used in */

/* many subsequence calls from this application to Windows. */

hInst = hInstance;

/* Create a main window for this application instance. */

hWnd = CreateWindow(

“GenericWClass”, /* See RegisterClass() call. */

“Generic Sample Application”, /* Text for window title bar. */

WS_OVERLAPPEDWINDOW, /* Window style. */

CW_USEDEFAULT, /* Default horizontal position. */

CW_USEDEFAULT, /* Default vertical position. */

CW_USEDEFAULT, /* Default width. */

CW_USEDEFAULT, /* Default height. */

NULL, /* Overlapped windows have no parent. */

NULL, /* Use the window class menu. */

hInstance, /* This instance owns this window. */

NULL /* Pointer not needed. */

);

/* If window could not be created, return “failure” */

if (!hWnd)

return (FALSE);

/* Make the window visible; update its client area; and return “success” */

ShowWindow(hWnd, nCmdShow); /* Show the window */

UpdateWindow(hWnd); /* Sends WM_PAINT message */

return (TRUE); /* Returns the value from PostQuitMessage */

}

/****************************************************************************

FUNCTION: MainWndProc(HWND, unsigned, WORD, LONG)

PURPOSE: Processes messages

MESSAGES:

WM_COMMAND - application menu (About dialog box)

WM_DESTROY - destroy window

COMMENTS:

To process the IDM_ABOUT message, call MakeProcInstance to get the

current instance address of the About function. Then call DialogBox,

which will create the box according to the information in your

generic.rc file and turn control over to the About function. When

it returns, free the instance address.

****************************************************************************/

long FAR PASCAL MainWndProc(hWnd, message, wParam, lParam)

HWND hWnd; /* window handle */

unsigned message; /* type of message */

WORD wParam; /* additional information */

LONG lParam; /* additional information */

{

FARPROC lpProcAbout; /* pointer to the “About” function */

switch (message) {

case WM_COMMAND: /* message: command from application menu */

if (wParam == IDM_ABOUT) {

lpProcAbout = MakeProcInstance(About, hInst);

DialogBox(hInst, /* current instance */

“AboutBox”, /* resource to use */

hWnd, /* parent handle */

lpProcAbout); /* About() instance address */

FreeProcInstance(lpProcAbout);

break;

}

else /* Lets Windows process it */

return (DefWindowProc(hWnd, message, wParam, lParam));

case WM_DESTROY: /* message: window being destroyed */

PostQuitMessage(0);

break;

default: /* Passes it on if unproccessed */

return (DefWindowProc(hWnd, message, wParam, lParam));

}

return (NULL);

}

/****************************************************************************

FUNCTION: About(HWND, unsigned, WORD, LONG)

PURPOSE: Processes messages for “About” dialog box

MESSAGES:

WM_INITDIALOG - initialize dialog box

WM_COMMAND - Input received

COMMENTS:

No initialization is needed for this particular dialog box, but TRUE

must be returned to Windows.

Wait for user to click on “OK” button, then close the dialog box.

*******************************************************************************/

BOOL FAR PASCAL About(hDlg, message, wParam, lParam)

HWND hDlg; /* window handle of the dialog box */

unsigned message; /* type of message */

WORD wParam; /* message-specific information */

LONG lParam;

{

switch (message) {

case WM_INITDIALOG: /* message: initialize dialog box */

return (TRUE);

case WM_COMMAND: /* message: received a command */

if (wParam == IDOK || /* “OK” box selected? */

wParam == IDCANCEL) { /* System menu close command? */

EndDialog(hDlg, TRUE); /* Exits the dialog box */

return (TRUE);

}

break;

}

return (FALSE); /* Didn't process a message */

}