Windows program design Reading Notes-Multithreading

I. multi-threaded Architecture

The main thread creates all the windows required by the program and includes all the window processes to process all the messages in these windows. Other threads only perform background processing, except for communication with the main thread, they do not communicate with users.

Events over 1/10 seconds (large jobs, such as spelling detection, database sorting, and printing) should not be placed in the message queue, but should be processed in a separate thread.

When the thread ends, the resources created by the thread are not automatically released.

 

Ii. multi-thread API:

Hthread = createthread (...)

DWORD winapi threadproc ([pvoid pparam)

 

_ Beginthread (...)

Void _ cdecl threadproc (void * pparam) // at the end of this function, there are usually _ endthread ();

 

Resumethread // restore the thread

 

Sleep (0) // The thread hand over the unfinished time slice.

 

Iii. msdn

Synchronization Functions

The following functions are used in synchronization.

Asynchronous Function	Description
Apcproc	An application-defined callback function used withQueueuserapcFunction.
Getoverlappedresult	Retrieves the results of an overlapped operation.
Queueuserapc	Adds a user-mode asynchronous procedure call (APC) object to the APC queue of the specified thread.

 

Critical-Section Function // critical section	Description
Deletecriticalsection	Releases all resources used by an unowned critical section object.
Entercriticalsection	Waits for ownership of the specified critical section object.
Initializecriticalsection	Initializes a critical section object.
Initializecriticalsectionandspincount	Initializes a critical section object and sets the spin count for the critical section.
Leavecriticalsection	Releases ownership of the specified critical section object.
Setcriticalsectionspincount	Sets the spin count for the specified critical section.
Tryentercriticalsection	Attempts to enter a critical section without blocking.

 

Event function // event object	Description
Createevent	Creates or opens a named or unnamed event object.
Openevent	Opens an existing named event object.
Pulseevent	Sets the specified event object to the signaled state and then resets it to the nonsignaled state after releasing the appropriate number of waiting threads.
Resetevent	Sets the specified event object to the nonsignaled state.
Setevent	Sets the specified event object to the signaled state.

 

Interlocked Function	Description
Interlockedcompareexchange	Performs an atomic comparison of the specified values and exchanges the values, based on the outcome of the comparison.
Interlockedcompareexchangepointer	Performs an atomic comparison of the specified values and exchange of the values, based on the outcome of the comparison.
Interlockeddecrement	Decrements (decreases by one) the value of the specified variable and checks the resulting value.
Interlockedexchange	Atomically exchanges a pair of values.
Interlockedexchangeadd	Performs an atomic addition of an increment value to an addend variable.
Interlockedexchangepointer	Atomically exchanges a pair of values.
Interlockedincrement	Increments (increases by one) the value of the specified variable and checks the resulting value.

 

Mutex function // mutex	Description
Createmutex	Creates or opens a named or unnamed mutex object.
Openmutex	Opens an existing named mutex object.
Releasemutex	Releases ownership of the specified mutex object.

 

Semaphore Function	Description
Createsemaphore	Creates or opens a named or unnamed semaphore object.
Opensemaphore	Opens an existing named semaphore object.
Releasesemaphore	Increases the count of the specified semaphore object by a specified amount.

 

Timer-queue timer function	Description
Changetimerqueuetimer	Updates a timer-queue timer.
Createtimerqueue	Creates a queue for timers.
Createtimerqueuetimer	Creates a timer-queue timer.
Deletetimerqueue	Deletes a timer queue.
Deletetimerqueueex	Deletes a timer queue.
Deletetimerqueuetimer	Cancels a timer-queue timer.

 

Wait Function	Description
Msgwaitformultipleobjects	Returns when the specified criteria for the specified objects is met.
Msgwaitformultipleobjectsex	Returns when the specified criteria for the specified objects is met.
Registerwaitforsingleobject	Directs a wait thread in the thread pool to wait on the object.
Signalobjectandwait	Allows the caller to atomically signal an object and wait on another object.
Unregisterwait	Cancels a registered wait operation.
Unregisterwaitex	Cancels a registered wait operation.
Waitformultipleobjects	Returns when the specified criteria for the specified objects is met.
Waitformultipleobjectsex	Returns when the specified criteria for the specified objects is met.
Waitforsingleobject	Returns when the specified criteria for the specified object is met.
Waitforsingleobjectex	Returns when the specified criteria for the specified object is met.
Waitortimercallback	Returns when the specified criteria is met.

 

Waitable timer function	Description
Cancelwaitabletimer	Sets the specified waitable timer to the inactive state.
Createwaitabletimer	Creates or opens a waitable timer object.
Openwaitabletimer	Opens an existing named waitable timer object.
Setwaitabletimer	Activates the specified waitable timer.
Timerapcproc	Application-defined timer completion routine used withSetwaitabletimerFunction.

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Annotation.

In the critical section, only one thread can enter the critical section at any time:

Init: bool isused = false; // indicates that no thread enters the critical section.

Enter: While (isused) {sleep (1);} isused = true;

Leave: isused = false;

The critical section can only be used for coordination between different threads in the same process. Coordination between different processes must be mutually exclusive.

 

Event object usage:

Initialization

Hevent = createevent (null, false, false, null );

Beginthread (thread, 0, & Params );

Thread functions:

Void thread (pvoid)
{

Hevent =... // obtain from pvoid
While (true)
{
Waitforsingleobject (hevent, infinite );
//.......... Subject
}
}

Start execution:

Setevent (hevent );