
- •The ministry of education and science of ukraine kharkiv national university of radio electronics
- •1. The Basics of Microsoft Foundation Classes
- •Mfc general information
- •A Framework of mfc-program
- •Creating the Application Class
- •Creating the Frame-Window Class
- •Declaring a Message Map and instantiation of application object global instance
- •Defining a Message Map
- •Messages and their processing in mfc-programs
- •Writing Message Map Functions
- •Message boxes and menus in mfc-programs
- •2. Dialog windows
- •2.1 Modal and modeless dialog windows
- •2.2 The control elements of dialog window
- •CListBox::AddString (lpctstr lpszItem ); // Call this member function to add a string (lpszItem) to a list box;
- •3. Additional control elements in mfc-programs. Working with icons, cursors, raster images
- •3.1 Additional control elements
- •Radio buttons
- •Afx_msg void cWnd::OnVScroll( uint nSbCode, uint nPos, cScrollBar* pScrollBar ); afx_msg void cWnd::OnHScroll( uint nSbCode, uint nPos, cScrollBar* pScrollBar );
- •Afx_msg void OnVScroll( uint nSbCode, uint nPos, cScrollBar* pScrollBar );
- •Working with icons, cursors, raster images
- •The icons and cursor registration
- •Icon and cursor loading
- •4. The elements of text processing in mfc
- •The redrawing problem decision
- •5. The Elements of working with graphics
- •5.1 The graphics functions.
- •Working with brushes
- •5.2 The mapping modes and output regions
- •6. Common control elements
- •Windows Common Controls
- •6.2 The toolbar using
- •On resizing, the message wm_size is sent and the standard handler OnSize() is called.
- •The working with Spins
- •The working with slider
- •To set the range (minimum and maximum positions) for the slider in a slider control use the following function:
- •The working with progress bar
- •The tree control using in mfc programs
- •Adding elements to the tree
- •The status bars usage
- •Bool cStatusBarCtrl::SetParts( int nParts, int* pWidths );
- •Tab controls using in mfc-programs
- •Int cTabCtrl::GetCurSel(); To Selects a tab in a tab control use SetCurSel() function:
- •Int cTabCtrl::SetCurSel( int nItem );
- •The property sheets and wizards
- •7. Thread multitasking and it’s implementation in mfc
- •7.1 The basic features of multitasking
- •7.2 The Synchronization
- •7.3 The working with semaphore
- •7. 4 The working with event object
- •8. The concept of Document view
- •8.1 Introduction to document conception
- •The control of documents storing
- •8.2 The dynamic creation of objects
- •The application framework creation
- •The main window and application classes creation
- •Listing 8.1 The example of main window class in Document / View concept
- •Listing 8.2 The example of document class in Document / View concept
- •8.3 The document framework creation
- •8.4 The initiation of application
- •8.5 The standard id’s, used in Document / View concept
- •9. The special types of menu and their implementation in mfc
- •9.1 The description of special menu styles
- •The mechanism to make changes in menus
- •9.2 The dynamic and floating menus implementation
- •CMenu::CreatePopupMenu
- •The example programs to work with dynamic menus
- •10. The system of help
- •10.1 The basic information on help structures
- •The call of help
- •The file of help
- •The Help file creating
- •The example of rtf file
- •10.2 The Help system including to the mfc-program
- •Parameters:
- •Return Values: If the function succeeds, the return value is nonzero. If the function fails, the return value is zero.
- •10.3 The handlers of help messages
- •The processing of help calls
- •Wm_commandhelp message processing
- •10.4 Wm_contextmenu message processing
- •11. Manipulating Device-Independent Bitmaps
- •11.1 The types of bitmap
- •11.2 The structures included to bitmap
- •Introducing the cDib Class
- •11.3 Programming the cDib Class
- •Loading a dib into Memory
- •Other cDib Member Functions
- •Creating ShowDib program
- •Modifying ShowDib's Resources
- •Adding Code to ShowDib
- •Examining the OnFileOpen() Function
- •Examining the OnDraw() Function
- •12. The elements of Database Programming
- •12.1 Understanding Database Concepts
- •Accessing a Database
- •12.2 Mfc odbc Classes
- •Registering the Database
- •Creating the Basic Employee Application
- •Creating the Database Display
- •Adding and Deleting Records
- •12.4 Sorting and Filtering
- •12.5 Odbc versus dao
- •13. Remote Automation
- •13.1 The introduction to Remote Automation
- •13.2 The Remote Automation Connection Manager and user components
- •13.3 Automation
- •Automation Clients
- •13.4 ActiveX
- •ActiveX Document Servers
- •ActiveX Document Containers
- •ActiveX Document Views
- •13.5 ActiveX Documents
- •ActiveX Controls
- •Interaction Between Controls with Windows and ActiveX Control Containers
- •13.6 Optimization of ActiveX Controls
- •13.7 Automation Servers
- •13.8 Connection Points
- •14. Microsoft DirectX and the main items of its using
- •14.2 The Component Object Model
- •IUnknown Interface
- •DirectX com Interfaces
- •DirectDraw Architecture
- •Other DirectDraw Features
- •Width and Pitch
- •14.5 Support for 3d Surfaces in DirectX
- •14.6 Direct3d Integration with DirectDraw
- •Direct3d Device Interface
- •Direct3d Texture Interface
- •The Basics of DirectDraw
- •Step 6: Writing to the Surface.The first half of the wm_timer message in ddex1 is devoted to writing to the back buffer, as shown in the following example:
- •Loading Bitmaps on the Back Buffer
- •Step 1: Creating the Palette. The ddex2 sample first loads the palette into a structure by using the following code:
- •Step 4: Flipping the Surfaces. Flipping surfaces in the ddex2 sample is essentially the same process as that in the first example. Blitting from an Off-Screen Surface
- •Step 1: Creating the Off-Screen Surfaces. The following code is added to the doInit function in ddex3 to create the two off-screen buffers:
- •Color Keys and Bitmap Animation
- •Dynamically Modifying Palettes
- •Optimizations and Customizations
- •Blitting with Color Fill
- •Determining the Capabilities of the Display Hardware
- •Storing Bitmaps in Display Memory
- •Triple Buffering
- •15. General information on OpenGl
- •15.1 Common information
- •Primitives and Commands
- •OpenGl Graphic Control
- •Execution Model
- •15.2 Basic OpenGl Operation
- •OpenGl Correctness Tips
- •15.3 OpenGl example program
- •Ph.D. Assosiate prof. Tsimbal Alexander m. System software, summary of lectures.
7.2 The Synchronization
Synchronizing resource access between threads is a common problem when writing multithreaded applications. Having two or more threads simultaneously access the same data can lead to undesirable and unpredictable results. For example, one thread could be updating the contents of a structure while another thread is reading the contents of the same structure. It is unknown what data the reading thread will receive: the old data, the newly written data, or possibly a mixture of both. MFC provides a number of synchronization and synchronization access classes to aid in solving this problem.
A typical multithreaded application has a class that represents a resource to be shared among threads. A properly designed, fully thread-safe class does not require you to call any synchronization functions. Everything is handled internally to the class, allowing you to concentrate on how to best use the class, not about how it might get corrupted. The best technique for creating a fully thread-safe class is to merge the synchronization class into the resource class. Merging the synchronization classes into the shared class is a straightforward process.
There are two states, which can be available for the task: 1) the task can be executed (or be ready for to execute); 2) the task can be blocked – it’s execution can be suspended until the needed resource will free or some event will happened.
The objects of synchronization
Win32 supports 4 types of synchronization objects. All of them are based on semaphore term:
A "classic semaphore" — synchronization object that allows a limited number of threads in one or more processes to access a resource. On that selection, the access to the resource or completely limited (the only one thread or process has an access to the resource in some moment of time), or the limited value of threads and resources have such access.
The semaphore is implemented as a counter, which decreases when task receives the semaphore and increases, when the task frees it.
The “exclusive semaphore” – mutex semaphore provides the complete access limitation to the resource. Such synchronization object allows one thread mutually exclusive access to a resource. Mutexes are useful when only one thread at a time can be allowed to modify data or some other controlled resource. For example, adding nodes to a linked list is a process that should only be allowed by one thread at a time.
The "event" — a synchronization object that allows one thread to notify another that an event has occurred. It’s used to lock the access to the resource until some process will not declare, that the given resource can be used. Events are useful when a thread needs to know when to perform its task. For example, a thread that copies data to a data archive would need to be notified when new data is available. The Object signalize on the required event complete.
The "critical section" — a synchronization object that allows one thread at a time to access a resource or section of code. Critical sections are useful when only one thread at a time can be allowed to modify data or some other controlled resource. For example, adding nodes to a linked list is a process that should only be allowed by one thread at a time.
The synchronization classes in MFC
The six multithreaded classes provided with MFC fall into two categories: synchronization objects (CSyncObject – the general class, which is the base class for the following: CSemaphore – the “classic” semaphore, CMutex – exclusive semaphore, CCriticalSection – the critical section, and CEvent – the event object) and synchronization access objects (CMultiLock and CSingleLock). The last two classes are supplementary. CMultiLock provides the access on two synchronization object, CSingleLock provides the access to one synchronization object.
Synchronization classes are used when access to a resource must be controlled to ensure integrity of the resource. Synchronization access classes are used to gain access to these controlled resources. To determine which synchronization class you should use, ask the following series of questions:
Does the application have to wait for something to happen before it can access the resource (for example, data must be received from a communications port before it can be written to a file)? If yes, use CEvent.
Can more than one thread within the same application access this resource at one time (for example, your application allows up to five windows with views on the same document)?
If yes, use CSemaphore.
Can more than one application use this resource (for example, the resource is in a DLL)? If yes, use CMutex. If no, use CCriticalSection.
An object of class CSingleLock represents the access-control mechanism used in controlling access to a resource in a multithreaded program. In order to use the synchronization classes CSemaphore, CMutex, CCriticalSection, and CEvent, you must create either a CSingleLock or CMultiLock object to wait on and release the synchronization object. Use CSingleLock when you only need to wait on one object at a time. Use CMultiLock when there are multiple objects that you could use at a particular time.
To use a CSingleLock object, call its constructor inside a member function in the controlled resource's class.
CSingleLock::CSingleLock ( CSyncObject* pObject, BOOL bInitialLock = FALSE );
Parameters:
pObject Points to the synchronization object to be accessed. Cannot be NULL.
bInitialLock Specifies whether to initially attempt to access the supplied object.
The access for the resource can be locked by Lock() function:
BOOL CSingleLock::Lock( DWORD dwTimeOut = INFINITE );
Parameters:
dwTimeOut Specifies the amount of time to wait for the synchronization object to be available (signaled). If INFINITE, Lock will wait until the object is signaled before returning
Then call the IsLocked member function to determine if the resource is available. If it is, continue with the remainder of the member function. If the resource is unavailable, either wait for a specified amount of time for the resource to be released, or return failure. After use of the resource is complete, either call the Unlock function if the CSingleLock object is to be used again, or allow the CSingleLock object to be destroyed.
BOOL CSingleLock::Unlock( );
BOOL CSingleLock::Unlock( LONG lCount, LPLONG lPrevCount = NULL );
CSingleLock objects require the presence of an object derived from CSyncObject. This is usually a data member of the controlled resource's class.
The general way to control the resource access
Create the object of CSyncObject (f.e. Semaphore) to control the resource access;
Create the object of CSingleLock object with the synchronization object;
Call the Lock() function to have the access to resource;
Make the operation with resource;
Call UnLock() function to free the semaphore.