/////////////////////////////////////////////////////////////////////////////
// Name: thread.h
-// Purpose: documentation for wxCondition class
+// Purpose: interface of wxCondition
// Author: wxWidgets team
// RCS-ID: $Id$
// Licence: wxWindows license
@library{wxbase}
@category{thread}
- @seealso
- wxThread, wxMutex
+ @see wxThread, wxMutex
*/
class wxCondition
{
public:
/**
- Default and only constructor. The @e mutex must be locked by the caller
+ Default and only constructor. The @a mutex must be locked by the caller
before calling Wait() function.
-
Use IsOk() to check if the object was successfully
initialized.
*/
Broadcasts to all waiting threads, waking all of them up. Note that this method
may be called whether the mutex associated with this condition is locked or
not.
-
- @sa Signal()
+
+ @see Signal()
*/
void Broadcast();
Returns @true if the object had been initialized successfully, @false
if an error occurred.
*/
-#define bool IsOk() /* implementation is private */
+ bool IsOk() const;
/**
Signals the object waking up at most one thread. If several threads are waiting
on the same condition, the exact thread which is woken up is undefined. If no
threads are waiting, the signal is lost and the condition would have to be
signalled again to wake up any thread which may start waiting on it later.
-
Note that this method may be called whether the mutex associated with this
condition is locked or not.
-
- @sa Broadcast()
+
+ @see Broadcast()
*/
void Signal();
/**
Waits until the condition is signalled.
-
This method atomically releases the lock on the mutex associated with this
condition (this is why it must be locked prior to calling Wait) and puts the
thread to sleep until Signal() or
Broadcast() is called. It then locks the mutex
again and returns.
-
Note that even if Signal() had been called before
Wait without waking up any thread, the thread would still wait for another one
and so it is important to ensure that the condition will be signalled after
Wait or the thread may sleep forever.
-
- @returns Returns wxCOND_NO_ERROR on success, another value if an error
- occurred.
-
- @sa WaitTimeout()
+
+ @return Returns wxCOND_NO_ERROR on success, another value if an error
+ occurred.
+
+ @see WaitTimeout()
*/
wxCondError Wait();
/**
Waits until the condition is signalled or the timeout has elapsed.
-
This method is identical to Wait() except that it
returns, with the return code of @c wxCOND_TIMEOUT as soon as the given
timeout expires.
-
+
@param milliseconds
- Timeout in milliseconds
+ Timeout in milliseconds
*/
wxCondError WaitTimeout(unsigned long milliseconds);
};
+
/**
@class wxCriticalSectionLocker
@wxheader{thread.h}
@library{wxbase}
@category{thread}
- @seealso
- wxCriticalSection, wxMutexLocker
+ @see wxCriticalSection, wxMutexLocker
*/
class wxCriticalSectionLocker
{
public:
/**
Constructs a wxCriticalSectionLocker object associated with given
- @e criticalsection and enters it.
+ @a criticalsection and enters it.
*/
wxCriticalSectionLocker(wxCriticalSection& criticalsection);
};
+
/**
@class wxThreadHelper
@wxheader{thread.h}
@library{wxbase}
@category{thread}
- @seealso
- wxThread
+ @see wxThread
*/
class wxThreadHelper
{
should call @ref wxThread::run GetThread()-Run to start running
it. You may optionally specify the stack size to be allocated to it (Ignored on
platforms that don't support setting it explicitly, eg. Unix).
-
- @returns One of:
+
+ @return One of:
*/
wxThreadError Create(unsigned int stackSize = 0);
/**
This is the entry point of the thread. This function is pure virtual and must
be implemented by any derived class. The thread execution will start here.
-
The returned value is the thread exit code which is only useful for
joinable threads and is the value returned by
@ref wxThread::wait GetThread()-Wait.
-
This function is called by wxWidgets itself and should never be called
directly.
*/
This is a public function that returns the wxThread object
associated with the thread.
*/
- wxThread * GetThread();
+ wxThread* GetThread();
/**
wxThread * m_thread
-
the actual wxThread object.
*/
};
+
/**
@class wxCriticalSection
@wxheader{thread.h}
A critical section object is used for exactly the same purpose as
- mutexes. The only difference is that under Windows platform
+ mutexes(). The only difference is that under Windows platform
critical sections are only visible inside one process, while mutexes may be
shared between processes, so using critical sections is slightly more
efficient. The terminology is also slightly different: mutex may be locked (or
@library{wxbase}
@category{thread}
- @seealso
- wxThread, wxCondition, wxCriticalSectionLocker
+ @see wxThread, wxCondition, wxCriticalSectionLocker
*/
class wxCriticalSection
{
};
+
/**
@class wxThread
@wxheader{thread.h}
also
makes it much easier to shoot oneself in the foot, so careful use of
synchronization
- objects such as mutexes or @ref overview_wxcriticalsection "critical sections"
- is recommended. In addition, don't create global thread
+ objects such as mutexes() or @ref overview_wxcriticalsection "critical
+ sections" is recommended. In addition, don't create global thread
objects because they allocate memory in their constructor, which will cause
problems for the memory checking system.
@library{wxbase}
@category{thread}
- @seealso
- wxMutex, wxCondition, wxCriticalSection
+ @see wxMutex, wxCondition, wxCriticalSection
*/
class wxThread
{
object. It
does not create or start execution of the real thread -- for this you should
use the Create() and Run() methods.
-
- The possible values for @e kind parameters are:
-
-
+ The possible values for @a kind parameters are:
+
@b wxTHREAD_DETACHED
-
-
+
Creates a detached thread.
-
+
@b wxTHREAD_JOINABLE
-
-
+
Creates a joinable thread.
*/
wxThread(wxThreadKind kind = wxTHREAD_DETACHED);
Delete() on it or wait until it terminates (and auto
destructs) itself. Because the detached threads delete themselves, they can
only be allocated on the heap.
-
Joinable threads should be deleted explicitly. The Delete() and Kill() functions
will not delete the C++ thread object. It is also safe to allocate them on
stack.
support setting it explicitly, eg. Unix system without
@c pthread_attr_setstacksize). If you do not specify the stack size,
the system's default value is used.
-
@b Warning: It is a good idea to explicitly specify a value as systems'
default values vary from just a couple of KB on some systems (BSD and
OS/2 systems) to one or several MB (Windows, Solaris, Linux). So, if you
use a lot of threads (say several hundred), virtual adress space can get tight
unless you explicitly specify a smaller amount of thread stack space for each
thread.
-
- @returns One of:
+
+ @return One of:
*/
wxThreadError Create(unsigned int stackSize = 0);
Calling Delete() gracefully terminates a
detached thread, either when the thread calls TestDestroy() or finished
processing.
-
(Note that while this could work on a joinable thread you simply should not
call this routine on one as afterwards you may not be able to call
Wait() to free the memory of that thread).
-
See @ref overview_deletionwxthread "wxThread deletion" for a broader
explanation of this routine.
*/
application has run into problems because the thread is using the default
behavior and has already deleted itself. Naturally, they instead attempt to
use joinable threads in place of the previous behavior.
-
However, polling a wxThread for when it has ended is in general a bad idea -
in fact calling a routine on any running wxThread should be avoided if
possible. Instead, find a way to notify yourself when the thread has ended.
Usually you only need to notify the main thread, in which case you can post
- an event to it via wxPostEvent or
+ an event to it via wxPostEvent() or
wxEvtHandler::AddPendingEvent. In
the case of secondary threads you can call a routine of another class
when the thread is about to complete processing and/or set the value
- of a variable, possibly using mutexes and/or other
+ of a variable, possibly using mutexes() and/or other
synchronization means if necessary.
*/
/**
This is the entry point of the thread. This function is pure virtual and must
be implemented by any derived class. The thread execution will start here.
-
The returned value is the thread exit code which is only useful for
joinable threads and is the value returned by Wait().
-
This function is called by wxWidgets itself and should never be called
directly.
*/
This is a protected function of the wxThread class and thus can only be called
from a derived class. It also can only be called in the context of this
thread, i.e. a thread can only exit from itself, not from another thread.
-
This function will terminate the OS thread (i.e. stop the associated path of
execution) and also delete the associated C++ object for detached threads.
OnExit() will be called just before exiting.
/**
Returns the number of system CPUs or -1 if the value is unknown.
-
- @sa SetConcurrency()
+
+ @see SetConcurrency()
*/
static int GetCPUCount();
thread throughout the system during its existence (i.e. the thread identifiers
may be reused).
*/
- unsigned long GetId();
+ unsigned long GetId() const;
/**
Gets the priority of the thread, between zero and 100.
-
The following priorities are defined:
-
-
+
@b WXTHREAD_MIN_PRIORITY
-
-
+
0
-
+
@b WXTHREAD_DEFAULT_PRIORITY
-
-
+
50
-
+
@b WXTHREAD_MAX_PRIORITY
-
-
+
100
*/
- int GetPriority();
+ int GetPriority() const;
/**
Returns @true if the thread is alive (i.e. started and not terminating).
-
Note that this function can only safely be used with joinable threads, not
detached ones as the latter delete themselves and so when the real thread is
no longer alive, it is not possible to call this function because
the wxThread object no longer exists.
*/
- bool IsAlive();
+ bool IsAlive() const;
/**
Returns @true if the thread is of the detached kind, @false if it is a
joinable
one.
*/
- bool IsDetached();
+ bool IsDetached() const;
/**
Returns @true if the calling thread is the main application thread.
/**
Returns @true if the thread is paused.
*/
- bool IsPaused();
+ bool IsPaused() const;
/**
Returns @true if the thread is running.
-
This method may only be safely used for joinable threads, see the remark in
IsAlive().
*/
- bool IsRunning();
+ bool IsRunning() const;
/**
Immediately terminates the target thread. @b This function is dangerous and
allocated to the thread will not be freed and the state of the C runtime library
may become inconsistent. Use Delete() for detached
threads or Wait() for joinable threads instead.
-
For detached threads Kill() will also delete the associated C++ object.
However this will not happen for joinable threads and this means that you will
still have to delete the wxThread object yourself to avoid memory leaks.
In neither case OnExit() of the dying thread will be
called, so no thread-specific cleanup will be performed.
-
This function can only be called from another thread context, i.e. a thread
cannot kill itself.
-
It is also an error to call this function for a thread which is not running or
paused (in the latter case, the thread will be resumed first) -- if you do it,
a @c wxTHREAD_NOT_RUNNING error will be returned.
thread associated with the wxThread object, not in the context of the main
thread. This function will not be called if the thread was
@ref kill() killed.
-
This function should never be called directly.
*/
void OnExit();
suspended immediately, under others it will only be suspended when it calls
TestDestroy() for the next time (hence, if the
thread doesn't call it at all, it won't be suspended).
-
This function can only be called from another thread context.
*/
wxThreadError Pause();
/**
Resumes a thread suspended by the call to Pause().
-
This function can only be called from another thread context.
*/
wxThreadError Resume();
/**
Starts the thread execution. Should be called after
Create().
-
This function can only be called from another thread context.
*/
-#define wxThreadError Run() /* implementation is private */
+ wxThreadError Run();
/**
Sets the thread concurrency level for this process. This is, roughly, the
number of threads that the system tries to schedule to run in parallel.
- The value of 0 for @e level may be used to set the default one.
-
+ The value of 0 for @a level may be used to set the default one.
Returns @true on success or @false otherwise (for example, if this function is
not implemented for this platform -- currently everything except Solaris).
*/
Sets the priority of the thread, between 0 and 100. It can only be set
after calling Create() but before calling
Run().
-
The following priorities are already defined:
-
-
+
@b WXTHREAD_MIN_PRIORITY
-
-
+
0
-
+
@b WXTHREAD_DEFAULT_PRIORITY
-
-
+
50
-
+
@b WXTHREAD_MAX_PRIORITY
-
-
+
100
*/
void SetPriority(int priority);
/**
Pauses the thread execution for the given amount of time.
-
- This function should be used instead of wxSleep by all worker
- threads (i.e. all except the main one).
+
+ This is the same as wxMilliSleep().
*/
static void Sleep(unsigned long milliseconds);
This function should be called periodically by the thread to ensure that calls
to Pause() and Delete() will
work. If it returns @true, the thread should exit as soon as possible.
-
Notice that under some platforms (POSIX), implementation of
Pause() also relies on this function being called, so
not calling it would prevent both stopping and suspending thread from working.
a thread
is undefined.
*/
- static wxThread * This();
+ static wxThread* This();
/**
There are two types of threads in wxWidgets: @e detached and @e joinable,
modeled after the the POSIX thread API. This is different from the Win32 API
where all threads are joinable.
-
By default wxThreads in wxWidgets use the detached behavior. Detached threads
delete themselves once they have completed, either by themselves when they
complete
are safe to create on the stack. Joinable threads also provide the ability
for one to get value it returned from Entry()
through Wait().
-
You shouldn't hurry to create all the threads joinable, however, because this
has a disadvantage as well: you @b must Wait() for a joinable thread or the
system resources used by it will never be freed, and you also must delete the
error. Notice that, unlike Delete() doesn't cancel the
thread in any way so the caller waits for as long as it takes to the thread to
exit.
-
You can only Wait() for joinable (not detached) threads.
-
This function can only be called from another thread context.
-
See @ref overview_deletionwxthread "wxThread deletion" for a broader
explanation of this routine.
*/
- ExitCode Wait();
+ ExitCode Wait() const;
/**
Give the rest of the thread time slice to the system allowing the other threads
a joinable thread on the heap, remember to delete it manually with the delete
operator or similar means as only detached threads handle this type of memory
management.
-
Since detached threads delete themselves when they are finished processing,
you should take care when calling a routine on one. If you are certain the
thread is still running and would like to end it, you may call
that the thread will be deleted after that call to Delete()). It should be
implied that you should never attempt to delete a detached thread with the
delete operator or similar means.
-
As mentioned, Wait() or
Delete() attempts to gracefully terminate
a joinable and detached thread, respectively. It does this by waiting until
the thread in question calls TestDestroy()
or ends processing (returns from wxThread::Entry).
-
Obviously, if the thread does call TestDestroy() and does not end the calling
thread will come to halt. This is why it is important to call TestDestroy() in
the Entry() routine of your threads as often as possible.
-
As a last resort you can end the thread immediately through
Kill(). It is strongly recommended that you
do not do this, however, as it does not free the resources associated with
wxApp::OnInit or your main function runs in, for
example) are considered "secondary threads". These include all threads created
by Create() or the corresponding constructors.
-
GUI calls, such as those to a wxWindow or
wxBitmap are explicitly not safe at all in secondary threads
and could end your application prematurely. This is due to several reasons,
including the underlying native API and the fact that wxThread does not run a
GUI event loop similar to other APIs as MFC.
-
- A workaround that works on some wxWidgets ports is calling wxMutexGUIEnter
- before any GUI calls and then calling wxMutexGUILeave afterwords. However,
+ A workaround that works on some wxWidgets ports is calling wxMutexGUIEnter()
+ before any GUI calls and then calling wxMutexGUILeave() afterwords. However,
the recommended way is to simply process the GUI calls in the main thread
- through an event that is posted by either wxPostEvent or
+ through an event that is posted by either wxPostEvent() or
wxEvtHandler::AddPendingEvent. This does
not imply that calls to these classes are thread-safe, however, as most
wxWidgets classes are not thread-safe, including wxString.
};
+
/**
@class wxSemaphore
@wxheader{thread.h}
{
public:
/**
- Specifying a @e maxcount of 0 actually makes wxSemaphore behave as if
+ Specifying a @a maxcount of 0 actually makes wxSemaphore behave as if
there is no upper limit. If maxcount is 1, the semaphore behaves almost as a
mutex (but unlike a mutex it can be released by a thread different from the one
which acquired it).
-
- @e initialcount is the initial value of the semaphore which must be between
- 0 and @e maxcount (if it is not set to 0).
+ @a initialcount is the initial value of the semaphore which must be between
+ 0 and @a maxcount (if it is not set to 0).
*/
wxSemaphore(int initialcount = 0, int maxcount = 0);
Increments the semaphore count and signals one of the waiting
threads in an atomic way. Returns wxSEMA_OVERFLOW if the count
would increase the counter past the maximum.
-
- @returns One of:
+
+ @return One of:
*/
wxSemaError Post();
/**
Same as Wait(), but returns immediately.
-
- @returns One of:
+
+ @return One of:
*/
wxSemaError TryWait();
/**
Wait indefinitely until the semaphore count becomes strictly positive
and then decrement it and return.
-
- @returns One of:
+
+ @return One of:
*/
wxSemaError Wait();
};
+
/**
@class wxMutexLocker
@wxheader{thread.h}
@library{wxbase}
@category{thread}
- @seealso
- wxMutex, wxCriticalSectionLocker
+ @see wxMutex, wxCriticalSectionLocker
*/
class wxMutexLocker
{
/**
Returns @true if mutex was acquired in the constructor, @false otherwise.
*/
-#define bool IsOk() /* implementation is private */
+ bool IsOk() const;
};
+
/**
@class wxMutex
@wxheader{thread.h}
@library{wxbase}
@category{thread}
- @seealso
- wxThread, wxCondition, wxMutexLocker, wxCriticalSection
+ @see wxThread, wxCondition, wxMutexLocker, wxCriticalSection
*/
class wxMutex
{
/**
Locks the mutex object. This is equivalent to
LockTimeout() with infinite timeout.
-
- @returns One of:
+
+ @return One of:
*/
wxMutexError Lock();
/**
Try to lock the mutex object during the specified time interval.
-
- @returns One of:
+
+ @return One of:
*/
wxMutexError LockTimeout(unsigned long msec);
/**
Tries to lock the mutex object. If it can't, returns immediately with an error.
-
- @returns One of:
+
+ @return One of:
*/
wxMutexError TryLock();
/**
Unlocks the mutex object.
-
- @returns One of:
+
+ @return One of:
*/
wxMutexError Unlock();
};
+
// ============================================================================
// Global functions/macros
// ============================================================================
+/** @ingroup group_funcmacro_thread */
+//@{
+
/**
- Returns @true if this thread is the main one. Always returns @true if
- @c wxUSE_THREADS is 0.
+ This macro declares a (static) critical section object named @a cs if
+ @c wxUSE_THREADS is 1 and does nothing if it is 0.
+
+ @header{wx/thread.h}
*/
-bool wxIsMainThread();
+#define wxCRIT_SECT_DECLARE(cs)
+
+/**
+ This macro declares a critical section object named @a cs if
+ @c wxUSE_THREADS is 1 and does nothing if it is 0. As it doesn't include
+ the @c static keyword (unlike wxCRIT_SECT_DECLARE()), it can be used to
+ declare a class or struct member which explains its name.
+
+ @header{wx/thread.h}
+*/
+#define wxCRIT_SECT_DECLARE_MEMBER(cs)
+
+/**
+ This macro creates a wxCriticalSectionLocker named @a name and associated
+ with the critical section @a cs if @c wxUSE_THREADS is 1 and does nothing
+ if it is 0.
+
+ @header{wx/thread.h}
+*/
+#define wxCRIT_SECT_LOCKER(name, cs)
/**
- This macro combines wxCRIT_SECT_DECLARE and
- wxCRIT_SECT_LOCKER: it creates a static critical
- section object and also the lock object associated with it. Because of this, it
- can be only used inside a function, not at global scope. For example:
+ This macro combines wxCRIT_SECT_DECLARE() and wxCRIT_SECT_LOCKER(): it
+ creates a static critical section object and also the lock object
+ associated with it. Because of this, it can be only used inside a function,
+ not at global scope. For example:
+
@code
int IncCount()
{
}
@endcode
- (note that we suppose that the function is called the first time from the main
- thread so that the critical section object is initialized correctly by the time
- other threads start calling it, if this is not the case this approach can
- @b not be used and the critical section must be made a global instead).
+ Note that this example assumes that the function is called the first time
+ from the main thread so that the critical section object is initialized
+ correctly by the time other threads start calling it, if this is not the
+ case this approach can @b not be used and the critical section must be made
+ a global instead.
+
+ @header{wx/thread.h}
*/
-#define wxCRITICAL_SECTION(name) /* implementation is private */
+#define wxCRITICAL_SECTION(name)
/**
- This macro declares a critical section object named @e cs if
- @c wxUSE_THREADS is 1 and does nothing if it is 0. As it doesn't
- include the @c static keyword (unlike
- wxCRIT_SECT_DECLARE), it can be used to declare
- a class or struct member which explains its name.
+ This macro is equivalent to
+ @ref wxCriticalSection::Leave "critical_section.Leave()" if
+ @c wxUSE_THREADS is 1 and does nothing if it is 0.
+
+ @header{wx/thread.h}
*/
-#define wxCRIT_SECT_DECLARE(cs) /* implementation is private */
+#define wxLEAVE_CRIT_SECT(critical_section)
+
+/**
+ This macro is equivalent to
+ @ref wxCriticalSection::Enter "critical_section.Enter()" if
+ @c wxUSE_THREADS is 1 and does nothing if it is 0.
+
+ @header{wx/thread.h}
+*/
+#define wxENTER_CRIT_SECT(critical_section)
+
+/**
+ Returns @true if this thread is the main one. Always returns @true if
+ @c wxUSE_THREADS is 0.
+
+ @header{wx/thread.h}
+*/
+bool wxIsMainThread();
/**
This function must be called when any thread other than the main GUI thread
- wants to get access to the GUI library. This function will block the execution
- of the calling thread until the main thread (or any other thread holding the
- main GUI lock) leaves the GUI library and no other thread will enter the GUI
- library until the calling thread calls ::wxMutexGuiLeave.
+ wants to get access to the GUI library. This function will block the
+ execution of the calling thread until the main thread (or any other thread
+ holding the main GUI lock) leaves the GUI library and no other thread will
+ enter the GUI library until the calling thread calls wxMutexGuiLeave().
Typically, these functions are used like this:
+
@code
void MyThread::Foo(void)
{
- // before doing any GUI calls we must ensure that this thread is the only
- // one doing it!
+ // before doing any GUI calls we must ensure that
+ // this thread is the only one doing it!
wxMutexGuiEnter();
}
@endcode
- Note that under GTK, no creation of top-level windows is allowed in any
- thread but the main one.
-
This function is only defined on platforms which support preemptive
threads.
+
+ @note Under GTK, no creation of top-level windows is allowed in any thread
+ but the main one.
+
+ @header{wx/thread.h}
*/
void wxMutexGuiEnter();
/**
- This macro declares a (static) critical section object named @e cs if
- @c wxUSE_THREADS is 1 and does nothing if it is 0.
-*/
-#define wxCRIT_SECT_DECLARE(cs) /* implementation is private */
+ This function is only defined on platforms which support preemptive
+ threads.
-/**
- This macro is equivalent to @ref wxCriticalSection::leave cs.Leave if
- @c wxUSE_THREADS is 1 and does nothing if it is 0.
-*/
-#define wxLEAVE_CRIT_SECT(wxCriticalSection& cs) /* implementation is private */
+ @see wxMutexGuiEnter()
-/**
- This macro creates a @ref overview_wxcriticalsectionlocker "critical section
- lock"
- object named @e name and associated with the critical section @e cs if
- @c wxUSE_THREADS is 1 and does nothing if it is 0.
+ @header{wx/thread.h}
*/
-#define wxCRIT_SECT_LOCKER(name, cs) /* implementation is private */
+void wxMutexGuiLeave();
-/**
- This macro is equivalent to @ref wxCriticalSection::enter cs.Enter if
- @c wxUSE_THREADS is 1 and does nothing if it is 0.
-*/
-#define wxENTER_CRIT_SECT(wxCriticalSection& cs) /* implementation is private */
+//@}
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