can a .cpp file call another .cpp file?

[kw1991]

I have two separate .cpp files in the a program and in the first.cpp file i have an empty function

void CBase::OnStart(DWORD dwArgc, PWSTR *pszArgv)
{
    //#include second.cpp??
}

when OnStart is run i want it to run all the code in second.cpp
can i do this and if so how?

i read that you should put all the functions into a new header file and then include that but i can't really do that because second.cpp if like a second program that does other things so i don't think moving the functions in a header file will help

[Vidminas]

You need to define your functions in *.cpp files, and then declare them in corresponding headers like:
function.cpp

void myFunction()
{
//Blah, blah, blah...
}

function.h

void myFunction();

and main.cpp

#include "function.h"
myFunction();

[coder777]

You shall not move the functions in the header, just the prototypes of the functions which are used somewhere else.

[kw1991]

this is the second .cpp i want to call:

#include "stdafx.h"
#include "resource.h"

#define TRAYICONID	1//				ID number for the Notify Icon
#define SWM_TRAYMSG	WM_APP//		the message ID sent to our window

#define SWM_SHOW	WM_APP + 1//	show the window
#define SWM_HIDE	WM_APP + 2//	hide the window
#define SWM_EXIT	WM_APP + 3//	close the window

// Global Variables:
HINSTANCE		hInst;	// current instance
NOTIFYICONDATA	niData;	// notify icon data

// Forward declarations of functions included in this code module:
BOOL				InitInstance(HINSTANCE, int);
BOOL				OnInitDialog(HWND hWnd);
void				ShowContextMenu(HWND hWnd);
ULONGLONG			GetDllVersion(LPCTSTR lpszDllName);

INT_PTR CALLBACK	DlgProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK	About(HWND, UINT, WPARAM, LPARAM);

int APIENTRY _tWinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPTSTR    lpCmdLine,
                     int       nCmdShow)
{
	MSG msg;
	HACCEL hAccelTable;

	// Perform application initialization:
	if (!InitInstance (hInstance, nCmdShow)) 
		return FALSE;
	hAccelTable = LoadAccelerators(hInstance, (LPCTSTR)IDC_STEALTHDIALOG);

	// Main message loop:
	while (GetMessage(&msg, NULL, 0, 0))
	{
		if (!TranslateAccelerator(msg.hwnd, hAccelTable, &msg)|| !IsDialogMessage(msg.hwnd,&msg) ) 
		{
			TranslateMessage(&msg);
			DispatchMessage(&msg);
		}
	}
	return (int) msg.wParam;
}

//	Initialize the window and tray icon
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
	// prepare for XP style controls
	InitCommonControls();

	 // store instance handle and create dialog
	hInst = hInstance;
	HWND hWnd = CreateDialog( hInstance, MAKEINTRESOURCE(IDD_DLG_DIALOG),
		NULL, (DLGPROC)DlgProc );
	if (!hWnd) 
		return FALSE;

	ZeroMemory(&niData,sizeof(NOTIFYICONDATA));

	ULONGLONG ullVersion = GetDllVersion(_T("Shell32.dll"));
	if(ullVersion >= MAKEDLLVERULL(5, 0,0,0))
		niData.cbSize = sizeof(NOTIFYICONDATA);
	else niData.cbSize = NOTIFYICONDATA_V2_SIZE;

	niData.uID = TRAYICONID;

	niData.uFlags = NIF_ICON | NIF_MESSAGE | NIF_TIP;

	niData.hIcon = (HICON)LoadImage(hInstance,MAKEINTRESOURCE(IDI_STEALTHDLG),
		IMAGE_ICON, GetSystemMetrics(SM_CXSMICON),GetSystemMetrics(SM_CYSMICON),
		LR_DEFAULTCOLOR);

	niData.hWnd = hWnd;
    niData.uCallbackMessage = SWM_TRAYMSG;

	// tooltip message
    lstrcpyn(niData.szTip, _T("Tooltip message goes here!"), sizeof(niData.szTip)/sizeof(TCHAR));

	Shell_NotifyIcon(NIM_ADD,&niData);


	if(niData.hIcon && DestroyIcon(niData.hIcon))
		niData.hIcon = NULL;

	return TRUE;
}

BOOL OnInitDialog(HWND hWnd)
{
	HMENU hMenu = GetSystemMenu(hWnd,FALSE);
	if (hMenu)
	{
		AppendMenu(hMenu, MF_SEPARATOR, 0, NULL);
		AppendMenu(hMenu, MF_STRING, IDM_ABOUT, _T("About"));
	}
	HICON hIcon = (HICON)LoadImage(hInst,
		MAKEINTRESOURCE(IDI_STEALTHDLG),
		IMAGE_ICON, 0,0, LR_SHARED|LR_DEFAULTSIZE);
	SendMessage(hWnd,WM_SETICON,ICON_BIG,(LPARAM)hIcon);
	SendMessage(hWnd,WM_SETICON,ICON_SMALL,(LPARAM)hIcon);
	return TRUE;
}

void ShowContextMenu(HWND hWnd)
{
	POINT pt;
	GetCursorPos(&pt);
	HMENU hMenu = CreatePopupMenu();
	if(hMenu)
	{
		if( IsWindowVisible(hWnd) )
			InsertMenu(hMenu, -1, MF_BYPOSITION, SWM_HIDE, _T("Hide"));
		else
			InsertMenu(hMenu, -1, MF_BYPOSITION, SWM_SHOW, _T("Show"));
		InsertMenu(hMenu, -1, MF_BYPOSITION, SWM_EXIT, _T("Exit"));

		SetForegroundWindow(hWnd);

		TrackPopupMenu(hMenu, TPM_BOTTOMALIGN,
			pt.x, pt.y, 0, hWnd, NULL );
		DestroyMenu(hMenu);
	}
}

// Get dll version number
ULONGLONG GetDllVersion(LPCTSTR lpszDllName)
{
    ULONGLONG ullVersion = 0;
	HINSTANCE hinstDll;
    hinstDll = LoadLibrary(lpszDllName);
    if(hinstDll)
    {
        DLLGETVERSIONPROC pDllGetVersion;
        pDllGetVersion = (DLLGETVERSIONPROC)GetProcAddress(hinstDll, "DllGetVersion");
        if(pDllGetVersion)
        {
            DLLVERSIONINFO dvi;
            HRESULT hr;
            ZeroMemory(&dvi, sizeof(dvi));
            dvi.cbSize = sizeof(dvi);
            hr = (*pDllGetVersion)(&dvi);
            if(SUCCEEDED(hr))
				ullVersion = MAKEDLLVERULL(dvi.dwMajorVersion, dvi.dwMinorVersion,0,0);
        }
        FreeLibrary(hinstDll);
    }
    return ullVersion;
}

// Message handler for the app
INT_PTR CALLBACK DlgProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
	int wmId, wmEvent;

	switch (message) 
	{
	case SWM_TRAYMSG:
		switch(lParam)
		{
		case WM_LBUTTONDBLCLK:
			ShowWindow(hWnd, SW_RESTORE);
			break;
		case WM_RBUTTONDOWN:
		case WM_CONTEXTMENU:
			ShowContextMenu(hWnd);
		}
		break;
	case WM_SYSCOMMAND:
		if((wParam & 0xFFF0) == SC_MINIMIZE)
		{
			ShowWindow(hWnd, SW_HIDE);
			return 1;
		}
		else if(wParam == IDM_ABOUT)
			DialogBox(hInst, (LPCTSTR)IDD_ABOUTBOX, hWnd, (DLGPROC)About);
		break;
	case WM_COMMAND:
		wmId    = LOWORD(wParam);
		wmEvent = HIWORD(wParam); 

		switch (wmId)
		{
		case SWM_SHOW:
			ShowWindow(hWnd, SW_RESTORE);
			break;
		case SWM_HIDE:
		case IDOK:
			ShowWindow(hWnd, SW_HIDE);
			break;
		case SWM_EXIT:
			DestroyWindow(hWnd);
			break;
		case IDM_ABOUT:
			DialogBox(hInst, (LPCTSTR)IDD_ABOUTBOX, hWnd, (DLGPROC)About);
			break;
		}
		return 1;
	case WM_INITDIALOG:
		return OnInitDialog(hWnd);
	case WM_CLOSE:
		DestroyWindow(hWnd);
		break;
	case WM_DESTROY:
		niData.uFlags = 0;
		Shell_NotifyIcon(NIM_DELETE,&niData);
		PostQuitMessage(0);
		break;
	}
	return 0;
}

// Message handler for about box.
LRESULT CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
	switch (message)
	{
	case WM_INITDIALOG:
		return TRUE;

	case WM_COMMAND:
		if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL) 
		{
			EndDialog(hDlg, LOWORD(wParam));
			return TRUE;
		}
		break;
	}
	return FALSE;
}

its code to create an icon in the system tray. i want this code to run in the function in the first post.
i don't know what to put in a header file for this

[kw1991]

so do i just put the functions in a header file like this?

BOOL OnInitDialog(HWND hWnd)
void ShowContextMenu(HWND hWnd)
ULONGLONG GetDllVersion(LPCTSTR lpszDllName)
...
etc

[coder777]

you cannot have two main()'s (_tWinMain()) in one program.

So it's the other way round. 'second.cpp' calls functions from 'first.cpp'

[kw1991]

heres what i am trying to do:
i have a windows service program that works fine.
in the OnStart() function i want the code to make the service into an icon run (which is second.cpp file)

[Bourgond Aries]

First of all, you can not "call" a .cpp file, what I think you mean is to call a function inside another .cpp file.

A very simple way to do this is:

source1.cpp:

int func2(); // This little prototype, tells the compiler that func2 actually exists, the linker will resolve the location of func2.

int func1()
{return func2();}

source2.cpp:

int func2()
{return 1;}

using a .hpp or .h file is basically the same, since the #include pastes the contents of the .h/.hpp file into the source file.

[kw1991]

@coder777 your right i can't have two main()'s
so i put second.cpp into a new solution file
but i still get the same error i got when i tried to run the files from the same solution:
error LNK2001: unresolved external symbol __imp__InitCommonControls@0
fatal error LNK1120: 1 unresolved externals

second.cpp works fine if its in a separate project but when i put everything into the one program file i get errors

[Bourgond Aries]

Creating a new solution separates the two files, they must be under the same project/solution so the linker can link them correctly.

[kw1991]

ok the files are under the same solution now and it builds successfully.
so how can i run second.cpp in first.cpp from the OnStart() function?

i tried doing what you suggested by creating the functions but i just got more errors

[Bourgond Aries]

You simply call the function from within OnStart()'s body. You can't run a .cpp file. I think you are confused, maybe you can post your error?

[kw1991]

yes but what is the function i'm calling?
i want to run the code in second.cpp in first.cpp (that's where the OnStart() function is)

[Bourgond Aries]

Well let's see, there are 7 functions in second.cpp:

APIENTRY _tWinMain
InitInstance
OnInitDialog
ShowContextMenu
GetDllVersion
DlgProc
About

in the function body of OnInit in first.cpp, you place the function calls to any of the above functions to run them.

[kw1991]

ok so OnStart() function in first.cpp now looks like this:

void CBase::OnStart(DWORD dwArgc, PWSTR *pszArgv)
{
	BOOL InitInstance(HINSTANCE, int);
	BOOL OnInitDialog(HWND hWnd);
	void ShowContextMenu(HWND hWnd);
	ULONGLONG GetDllVersion(LPCTSTR lpszDllName);

	INT_PTR CALLBACK DlgProc(HWND, UINT, WPARAM, LPARAM);
	LRESULT CALLBACK About(HWND, UINT, WPARAM, LPARAM);

	int APIENTRY _tWinMain(HINSTANCE hInstance,
		HINSTANCE hPrevInstance,
		LPTSTR    lpCmdLine,
		int       nCmdShow);

}

is that right?
it builds successfully

[Bourgond Aries]

You are not calling them, merely declaring them as you are not passing arguments.

To call one (example):
InitInstance(x, 32);
(I don't know what you pass as HINSTANCE, that must be windows specific if I'm not mistaken.)

[kw1991]

but i am not sure what values to pass
i know this won't work either..

        BOOL InitInstance();
	BOOL OnInitDialog();
	void ShowContextMenu();
	ULONGLONG GetDllVersion();
	INT_PTR CALLBACK DlgProc();
	LRESULT CALLBACK About();
	int APIENTRY _tWinMain();

so how do i call the functions from second.cpp to the OnStart() function in first.cpp?

[Bourgond Aries]

You'll need to know what to pass. Since I assume these are windows function calls, try asking in the windows section.

[coder777]

@Bourgond Aries
Sorry, but you don't know what you're talking about

@kw1991

_tWinMain is your entry point. Leave it like it is.
In case of a service dwArgc / pszArgv don't have any meaning.

What you need for your server is a thread.
Turn your current second main from 'first.cpp' into a thread function and start it from InitInstance();

[EDIT]
The link error is something else. You need to add the library

Comctl32.lib

to your project

[Bourgond Aries]

@coder777
What did I get wrong?