#DELPHI XE10 THREAD SAFE QUEUE WINDOWS#

The best place to call CheckSynchronize is when the application is idle (for example, from an OnIdle event handler).

While list objects are not thread-safe, you can use a thread-safe version, TThreadList, instead of TList.Р”В¬all the CheckSynchronize routine periodically within the main thread of your application so that background threads can synchronize their execution with the main thread.Canvas objects can be used outside the Synchronize method by locking them (see 'Locking objects' on page 13-8). You do not need to use the main VCL or CLX thread to access TFont, TPen, TBrush, TBitmap, TMetafile (VCL only), TDrawing (CLX only), or TIcon.

Thus, for example, you need to synchronize calls that link a data control to a dataset by setting the DataSet property of the data source object, but you don't need to synchronize to access the data in a field of the dataset.Р”Р‡or more information about using database sessions with threads in BDE-enabled applications, see 'Managing multiple sessions' on page 26-29. When using data access components, you must still wrap all calls that involve data-aware controls in the Synchronize method. ADO and InterBaseExpress components are thread-safe. For dbExpress, as long as the vendor client library is thread-safe, the dbExpress components will be thread-safe. The one exception to this is when you are using Microsoft Access drivers, which are built using a Microsoft library that is not thread-safe.

Data access components are thread-safe as follows: For BDE-enabled datasets, each thread must have its own database session component.

You do not need to use the Synchronize method for the following objects: Omitting the use of the Synchronize method when you know an object's methods are thread-safe will improve performance because you don't need to wait for the VCL or CLX thread to enter its message loop. You do not always need to use the main thread. You must use other mechanisms, such as critical sections, to protect access to VCL or CLX objects in console applications. Note Because Synchronize uses the message loop, it does not work in console applications. Synchronize waits for the main thread to enter the message loop and then executes the passed method. Call this separate routine from within your thread's Synchronize method. To use the main thread, create a separate routine that performs the required actions. If all objects access their properties and execute their methods within this single thread, you need not worry about your objects interfering with each other.

#DELPHI XE10 THREAD SAFE QUEUE WINDOWS#

This is the thread that handles all Windows messages received by components in your application. Because of this, a main thread is set aside to access VCL and CLX objects. That is, accessing properties or executing methods may perform some actions that use memory which is not protected from the actions of other threads. When you use objects from the class hierarchy, their properties and methods are not guaranteed to be thread-safe. On the other hand, because the thread shares the same process space with other threads, you can use the shared memory to communicate between threads. Writing the thread function is a little trickier than writing a separate program because you must make sure that you don't overwrite memory that is used by other threads in your application. You can think of it as a program that is launched by your application, except that it shares the same process space. The Execute method is your thread function.

Delphi xe10 thread safe queue