A message box displays a simple message to the user but may include some selection options. They are typically used to inform the user that an event has taken place. To create a message box use the API function call MessageBox. The prototype for this function is
int MessageBox(HWND hWnd,LPCTSTR lpText,LPCTSTR lpCaption,UINT uType);
where
hWnd – is a handle to the owner window of the message box to be created. If this parameter is NULL, the message box has no owner window.
LpText – The message to be displayed.
LpCaption – Contains dialog box title. If this parameter is NULL, the default title is Error
UType – defines the contents and behaviour of the dialog box and will be a combination of a number of different flag value but some of the more common values are
| MB_ABORTRETRYIGNORE- The message box contains three pushbuttons: Abort, Retry, and Ignore. MB_ICONEXCLAMATION-An exclamation-point icon appears in the message box. MB_ICONERROR-A stop-sign icon appears in the message box. MB_ICONINFORMATION – An icon consisting of a lowercase letter i in a circle appears in the message box. MB_ICONQUESTION-A question-mark icon appears in the message box MB_ICONSTOP- A stop-sign icon appears in the message box. MB_OK – The message box contains one pushbutton: OK. This is the default. MB_OKCANCEL – The message box contains two push buttons: OK and Cancel. MB_RETRYCANCEL – The message box contains two push buttons: Retry and Cancel. MB_YESNO – The message box contains two push buttons: Yes and No. MB_YESNOCANCEL – The message box contains three pushbuttons: Yes, No, and Cancel. |
The return value will depend on the type of message box selected but will be one of the following: IDABORT, IDCANCEL, IDCONTINUE, IDIGNORE, IDNO, IDOK, IDRETRY, IDYES
For further detailed reading
https://docs.microsoft.com/en-us/windows/win32/api/winuser/nf-winuser-messagebox
The following short program displays a very simple message box
#include <windows.h>
int APIENTRY WinMain( HINSTANCE hInst, HINSTANCE hPrev, LPSTR lpCmdLine, int nCmdShow )
{
MessageBox( NULL, "Hello, World!", "Hi!", MB_OK );
return 0;
}