Table of Contents
What is Wm_powerbroadcast?
WM_POWERBROADCAST messages do not distinguish between different low-power states. An application can determine only that the system is entering or has resumed from a low-power state; it cannot determine the specific power state. The system records details about power state transitions in the Windows System event log.
What is Lresult callback?
LRESULT is an integer value that your program returns to Windows. It contains your program’s response to a particular message. The meaning of this value depends on the message code. CALLBACK is the calling convention for the function.
What is Wndproc function?
A callback function, which you define in your application, that processes messages sent to a window. The WNDPROC type defines a pointer to this callback function. The WndProc name is a placeholder for the name of the function that you define in your application.
What happens when any keyboard key is pressed about Wm_char message?
Posted to the window with the keyboard focus when a WM_KEYDOWN message is translated by the TranslateMessage function. The WM_CHAR message contains the character code of the key that was pressed.
What is TranslateMessage?
TranslateMessage() converts virtual keys messages to character input messages. It is a separate call for the remote chance that under certain circumstances you would want to not produce character input messages for certain virtual keys. Highly active question.
What is GetProcAddress API?
GetProcAddress verifies that the specified ordinal is in the range 1 through the highest ordinal value exported in the . def file. The function then uses the ordinal as an index to read the function’s address from a function table.
What is GetAsyncKeyState?
GetAsyncKeyState stands for Get Asynchronous Key State in C++. This function gives information about the key, whether the key was pressed up or down at the time when the function is called. In simple words, it will check whether a key is pressed or not.
Can callback be synchronous?
The callback is a function that’s accepted as an argument and executed by another function (the higher-order function). There are 2 kinds of callback functions: synchronous and asynchronous. The synchronous callbacks are executed at the same time as the higher-order function that uses the callback.
What is AWT frame?
A Frame is a top-level window with a title and a border. The default layout for a frame is BorderLayout. Frames are capable of generating the following types of window events: WindowOpened, WindowClosing, WindowClosed, WindowIconified, WindowDeiconified, WindowActivated, WindowDeactivated.
Which class is a subclass of component?
The Container class is a special subclass of Component : it is a type of component that can contain other components and arranges them visually. The Container class, like Component is an abstract class.
What do the wParam and lParam parameters actually mean?
The actual meaning of the wParam and lParam parameters’ content depends on the particular message being sent; they are just generic buckets for message parameters. So it’s quite likely that you won’t be able to circumvent unsafe type casts. Show activity on this post.
What is HWND and wParam?
This parameter is typically named hWnd. The message. This parameter is typically named uMsg. For lists of the system-provided messages, see System-defined messages. Additional message information. This parameter is typically named wParam. The contents of the wParam parameter depend on the value of the uMsg parameter. Additional message information.
Is wParam 32 bit or 64 bit?
When Windows was converted to 32-bit, the WPARAM parameter grew to a 32-bit value as well. So even though the “W” stands for “word”, it isn’t a word any more. (And in 64-bit Windows, both parameters are 64-bit values!)
What are the contents of the lParam and uMsg parameters?
The contents of the lParam parameter depend on the value of the uMsg parameter. The return value is the result of the message processing, and depends on the message sent.