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Authors
- Scott Christley (
scottc@net-community.com
)
-
- Andrew Kachites McCallum (
mccallum@gnu.ai.mit.edu
)
-
- Richard Frith-Macdonald (
richard@brainstorm.co.uk
)
-
- Nicola Pero (
n.pero@mi.flashnet.it
)
-
Version: 24000
Date: 2006-10-31 00:05:46 -0700 (Tue, 31 Oct 2006)
Copyright: (C) 1996-2000 Free Software Foundation, Inc.
- Declared in:
- Foundation/NSThread.h
Availability: OpenStep
This class encapsulates OpenStep threading. See
NSLock
and its subclasses for handling synchronisation between
threads.
Each process begins with a main
thread and additional threads can be created using
NSThread. The GNUstep implementation of OpenStep
has been carefully designed so that the internals of
the base library do not use threading (except for
methods which explicitly deal with threads of
course) so that you can write applications without
threading. Non-threaded applications are more
efficient (no locking is required) and are easier
to debug during development.
Instance Variables
Method summary
+ (
NSThread*)
currentThread;
Availability: OpenStep
Returns the NSThread object corresponding to the
current thread.
NB. In GNUstep the library internals use the
GSCurrentThread()
function as a more efficient mechanism for doing
this job - so you cannot use a category to override
this method and expect the library internals to use
your implementation.
+ (void)
detachNewThreadSelector: (SEL)aSelector
toTarget: (id)aTarget
withObject: (id)anArgument;
Availability: OpenStep
Create a new thread - use this method rather than
alloc-init. The new thread will begin
executing the message given by
aSelector, aTarget, and
anArgument. This should have no return
value, and must set up an autorelease pool if
retain/release memory management is used.
It should free this pool before it finishes execution.
+ (void)
exit;
Availability: OpenStep
Terminates the current thread.
Normally
you don't need to call this method explicitly, since
exiting the method with which the thread was
detached causes this method to be called
automatically.
+ (BOOL)
isMultiThreaded;
Availability: OpenStep
Returns a flag to say whether the application is
multi-threaded or not.
An application
is considered to be multi-threaded if any thread other
than the main thread has been started, irrespective of
whether that thread has since terminated.
NB. This method returns YES
if called
within a handler processing
NSWillBecomeMultiThreadedNotification
+ (void)
setThreadPriority: (double)pri;
Availability: OpenStep
Set the priority of the current thread. This is a value
in the range 0.0 (lowest) to 1.0 (highest) which is
mapped to the underlying system priorities. The
current gnu objc runtime supports three priority
levels which you can obtain using values of 0.0,
0.5, and 1.0
+ (void)
sleepUntilDate: (
NSDate*)date;
Availability: OpenStep
Delaying a thread... pause until the specified
date.
+ (double)
threadPriority;
Availability: OpenStep
Return the priority of the current thread.
- (
NSMutableDictionary*)
threadDictionary;
Availability: OpenStep
Return the thread dictionary. This dictionary can be
used to store arbitrary thread specific data.
NB. This cannot be autoreleased, since we cannot be
sure that the autorelease pool for the thread will
continue to exist for the entire life of the
thread!
Instance Variables for NSThread Class
@public BOOL _active;
Availability: OpenStep
Warning the underscore at the start of the
name of this instance variable indicates that, even
though it is not technically private, it is
intended for internal use within the package, and
you should not use the variable in other code.
@protected id _arg;
Availability: OpenStep
Warning the underscore at the start of the
name of this instance variable indicates that, even
though it is not technically private, it is
intended for internal use within the package, and
you should not use the variable in other code.
@public struct autorelease_thread_vars _autorelease_vars;
Availability: OpenStep
Warning the underscore at the start of the
name of this instance variable indicates that, even
though it is not technically private, it is
intended for internal use within the package, and
you should not use the variable in other code.
@public NSHandler* _exception_handler;
Availability: OpenStep
Warning the underscore at the start of the
name of this instance variable indicates that, even
though it is not technically private, it is
intended for internal use within the package, and
you should not use the variable in other code.
@public id _gcontext;
Availability: OpenStep
Warning the underscore at the start of the
name of this instance variable indicates that, even
though it is not technically private, it is
intended for internal use within the package, and
you should not use the variable in other code.
@protected SEL _selector;
Availability: OpenStep
Warning the underscore at the start of the
name of this instance variable indicates that, even
though it is not technically private, it is
intended for internal use within the package, and
you should not use the variable in other code.
@protected id _target;
Availability: OpenStep
Warning the underscore at the start of the
name of this instance variable indicates that, even
though it is not technically private, it is
intended for internal use within the package, and
you should not use the variable in other code.
@public NSMutableDictionary* _thread_dictionary;
Availability: OpenStep
Warning the underscore at the start of the
name of this instance variable indicates that, even
though it is not technically private, it is
intended for internal use within the package, and
you should not use the variable in other code.
- Declared in:
- Foundation/NSThread.h
Availability: Base 10.0.0
Extra methods to permit messages to be sent to an
object such that they are executed in the
main thread.
The main thread is the
thread in which the GNUstep system is started, and
where the GNUstep gui is used, it is the thread in
which gui drawing operations must be
performed.
Method summary
- (void)
performSelectorOnMainThread: (SEL)aSelector
withObject: (id)anObject
waitUntilDone: (BOOL)aFlag;
Availability: Base 10.0.0
- (void)
performSelectorOnMainThread: (SEL)aSelector
withObject: (id)anObject
waitUntilDone: (BOOL)aFlag
modes: (
NSArray*)anArray;
Availability: Base 10.0.0
This method performs aSelector on the
receiver, passing anObject as an
argument, but does so in the main thread of the
program. The receiver and anObject
are both retained until the method is performed.
The selector is performed when the runloop of the
main thread next runs in one of the modes specified
in anArray.
Where this method has
been called more than once before the runloop of the
main thread runs in the required mode, the order in
which the operations in the main thread is done is
the same as that in which they were added using this
method.
If there are no modes in anArray, the
method has no effect and simply returns
immediately.
The argument aFlag specifies whether the
method should wait until the selector has been
performed before returning.
NB. This method does
not cause the runloop of the main thread to
be run... so if the runloop is not executed by some
code in the main thread, the thread waiting for the
perform to complete will block forever.
As a special case, if aFlag ==
YES
and the current thread is the
main thread, the modes array is ignored and the
selector is performed immediately. This behavior
is necessary to avoid the main thread being blocked by
waiting for a perform which will never happen
because the runloop is not executing.
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