What Are Threads? Threads are about doing things in parallel, just like processes. So how do threads differ from processes? While you are making calculations on a spreadsheet, there may also be a media player running on the same desktop playing your favorite song. Here is an example of two processes working in parallel: one running the spreadsheet program; one running a media player. Multitasking is a well known term for this. A closer look at the media player reveals that there are again things going on in parallel within one single process.

Modify Qt GUI from background worker thread. In main thread will actually update text. Stuff that is new to me in QT! I'm having the problem of the UI locking. Qt Programming; Update GUI from another thread. But I just can't figure out how to update the GUI from the separate thread. Update GUI from another thread Hi. Sep 08, 2008 Updating the GUI by multiple threads.NET Framework. But the problem is that at one timer only one thread updates the user interface. More Qt Update Ui From Thread videos.

While the media player is sending music to the audio driver, the user interface with all its bells and whistles is being constantly updated. This is what threads are for -- concurrency within one single process. So how is concurrency implemented? Parallel work on single core CPUs is an illusion which is somewhat similar to the illusion of moving images in cinema. For processes, the illusion is produced by interrupting the processor's work on one process after a very short time. Then the processor moves on to the next process.

In order to switch between processes, the current program counter is saved and the next processor's program counter is loaded. This is not sufficient because the same needs to be done with registers and certain architecture and OS specific data. Just as one CPU can power two or more processes, it is also possible to let the CPU run on two different code segments of one single process. When a process starts, it always executes one code segment and therefore the process is said to have one thread. However, the program may decide to start a second thread.

Then, two different code sequences are processed simultaneously inside one process. Concurrency is achieved on single core CPUs by repeatedly saving program counters and registers then loading the next thread's program counters and registers. No cooperation from the program is required to cycle between the active threads. A thread may be in any state when the switch to the next thread occurs. The current trend in CPU design is to have several cores. A typical single-threaded application can make use of only one core.

However, a program with multiple threads can be assigned to multiple cores, making things happen in a truly concurrent way. As a result, distributing work to more than one thread can make a program run much faster on multicore CPUs because additional cores can be used. GUI Thread and Worker Thread As mentioned, each program has one thread when it is started. This thread is called the 'main thread' (also known as the 'GUI thread' in Qt applications). Bagian Dari Microsoft Word Dan Fungsinya. The Qt GUI must run in this thread. All widgets and several related classes, for example, don't work in secondary threads.

A secondary thread is commonly referred to as a 'worker thread' because it is used to offload processing work from the main thread. Simultaneous Access to Data Each thread has its own stack, which means each thread has its own call history and local variables. Unlike processes, threads share the same address space. The following diagram shows how the building blocks of threads are located in memory. Program counter and registers of inactive threads are typically kept in kernel space. Patch Lancer 1.4.