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The sentinel value is a form of in-band data that makes it possible to detect the end of the data when no out-of-band data (such as an explicit size indication) is provided. The value should be selected in such a way that it is guaranteed to be distinct from all legal data values since otherwise, the presence of such values would prematurely ...
In the strictest sense, an event loop is one of the methods for implementing inter-process communication. In fact, message processing exists in many systems, including a kernel-level component of the Mach operating system. The event loop is a specific implementation technique of systems that use message passing.
The message loop is an obligatory section of code in every program that uses a graphical user interface under Microsoft Windows. [1] Windows programs that have a GUI are event-driven. Windows maintains an individual message queue for each thread that has created a window. Usually only the first thread creates windows.
In many programming languages, only integers can be reliably used in a count-controlled loop. Floating-point numbers are represented imprecisely due to hardware constraints, so a loop such as. for X := 0.1 step 0.1 to 1.0 do. might be repeated 9 or 10 times, depending on rounding errors and/or the hardware and/or the compiler version.
Most operating systems (including Solaris, Mac OS X and FreeBSD) use a hybrid approach called "adaptive mutex". The idea is to use a spinlock when trying to access a resource locked by a currently-running thread, but to sleep if the thread is not currently running. (The latter is always the case on single-processor systems.) [8]
A busy waiting loop while not ( P) do skip. will not work, as mutual exclusion will prevent any other thread from entering the monitor to make the condition true. Other "solutions" exist such as having a loop that unlocks the monitor, waits a certain amount of time, locks the monitor and checks for the condition P. Theoretically, it works and ...
Control.Cursor is the cursor shown when the mouse is in the control's region; System.Windows.Forms.Cursor.Current is the cursor shown when the mouse enters any window of the application. [2] For long term wait cursors, the UseWaitCursor property can be set (either Control level or application level) on one occasion and reset at another time. [2]
A control loop is the fundamental building block of control systems in general and industrial control systems in particular. It consists of the process sensor, the controller function, and the final control element (FCE) which controls the process necessary to automatically adjust the value of a measured process variable (PV) to equal the value of a desired set-point (SP).