glibmm: Glib::Thread Class Reference

glibmm 2.66.4

Classes | Public Member Functions | Static Public Member Functions | Related Functions | List of all members
Glib::Thread Class Reference

Represents a running thread. More...

`#include <glibmm/thread.h>`

## Classes
class | Exit
| Exception class used to exit from a thread. More...

## Public Member Functions
| Thread (const Thread &)=delete
Thread & | operator= (const Thread &)=delete
void | join ()
| Waits until the thread finishes. More...
bool | joinable () const
| Returns whether the thread is joinable. More...
void | set_priority (ThreadPriority priority)
| Changes the priority of the thread to priority. More...
ThreadPriority | get_priority () const
| Returns the priority of the thread. More...
GThread * | gobj ()
const GThread * | gobj () const

## Static Public Member Functions
static Thread * | create (const sigc::slot< void > & slot, bool joinable=true)
| Creates a new thread with the priority `THREAD_PRIORITY_NORMAL`. More...
static Thread * | self ()
| Returns the Thread* corresponding to the calling thread. More...
static Thread * | create (const sigc::slot< void > & slot, unsigned long stack_size, bool joinable, bool bound, ThreadPriority priority)
| Creates a new thread with the priority priority. More...
static void | yield ()
| Gives way to other threads waiting to be scheduled. More...

## Related Functions
(Note that these are not member functions.)
Thread * | wrap (GThread * gobject)

## Detailed Description

Represents a running thread.

An instance of this class can only be obtained with create(), self(), or wrap(GThread*). It's not possible to delete a Thread object. If the thread is not joinable, its resources will be freed automatically when it exits. Otherwise, if the thread is joinable, you must call join() to avoid a memory leak.

Note
  g_thread_exit() is not wrapped, because that function exits a thread without any cleanup. That's especially dangerous in C++ code, since the destructors of automatic objects won't be invoked. Instead, you can throw a Thread::Exit exception, which will be caught by the internal thread entry function.
  You might have noticed that the thread entry slot doesn't have the usual void* return value. If you want to return any data from your thread you can pass an additional output argument to the thread's entry slot.

Deprecated:
  Use Glib::Threads::Thread instead.

## Constructor & Destructor Documentation

## ◆ Thread()

Glib::Thread::Thread | ( | const Thread & |  | ) |
| delete

## Member Function Documentation

## ◆ create() [1/2]

static Thread* Glib::Thread::create | ( | const sigc::slot< void > & | slot,
|  | bool | joinable = `true`
| ) |  |
| static

Creates a new thread with the priority `THREAD_PRIORITY_NORMAL`.

If joinable is `true`, you can wait for this thread's termination by calling join(). Otherwise the thread will just disappear, when ready.

The new thread executes the function or method slot points to. You can pass additional arguments using sigc::bind(). If the thread was created successfully, it is returned, otherwise a ThreadError exception is thrown.

Because sigc::trackable is not thread safe, if the slot represents a non-static class method (that is, it is created by sigc::mem_fun()), the class concerned should not derive from sigc::trackable.

Parameters

  slot | A slot to execute in the new thread.
  joinable | This parameter is now ignored because Threads are now always joinable.

Returns
  The new Thread* on success.

Exceptions

  Glib::ThreadError |

## ◆ create() [2/2]

static Thread* Glib::Thread::create | ( | const sigc::slot< void > & | slot,
|  | unsigned long | stack_size,
|  | bool | joinable,
|  | bool | bound,
|  | ThreadPriority | priority
| ) |  |
| static

Creates a new thread with the priority priority.

The stack gets the size stack_size or the default value for the current platform, if stack_size is `0`.

If joinable is `true`, you can wait for this thread's termination by calling join(). Otherwise the thread will just disappear, when ready. If bound is `true`, this thread will be scheduled in the system scope, otherwise the implementation is free to do scheduling in the process scope. The first variant is more expensive resource-wise, but generally faster. On some systems (e.g. Linux) all threads are bound.

The new thread executes the function or method slot points to. You can pass additional arguments using sigc::bind(). If the thread was created successfully, it is returned.

Because sigc::trackable is not thread safe, if the slot represents a non-static class method (that is, it is created by sigc::mem_fun()), the class concerned should not derive from sigc::trackable.

Note
  It is not guaranteed, that threads with different priorities really behave accordingly. On some systems (e.g. Linux) only root can increase priorities. On other systems (e.g. Solaris) there doesn't seem to be different scheduling for different priorities. All in all try to avoid being dependent on priorities. Use `Glib::THREAD_PRIORITY_NORMAL` here as a default.
  Only use the extended create(const sigc::slot<void>&, unsigned long, bool, bool, ThreadPriority) function, when you really can't use the simple create(const sigc::slot<void>&, bool) instead. The latter overload does not take stack_size, bound and priority as arguments, as they should only be used for cases, where it is inevitable.

Parameters

  slot | A slot to execute in the new thread.
  stack_size | A stack size for the new thread, or `0`.
  joinable | Should this thread be joinable?
  bound | Should this thread be bound to a system thread?
  priority | A priority for the thread.

Returns
  The new Thread* on success.

Exceptions

  Glib::ThreadError |

Deprecated:
  Use the simpler create() method instead, because all Threads are now joinable, and bounds and priority parameters now have no effect.

## ◆ get_priority()

ThreadPriority Glib::Thread::get_priority | ( |  | ) | const

Returns the priority of the thread.

Returns
  The thread's priority.

Deprecated:
  Thread priorities no longer have any effect.

## ◆ gobj() [1/2]

GThread* Glib::Thread::gobj | ( |  | ) |
| inline

## ◆ gobj() [2/2]

const GThread* Glib::Thread::gobj | ( |  | ) | const
| inline

## ◆ join()

void Glib::Thread::join | ( |  | ) |

Waits until the thread finishes.

Waits until the thread finishes, i.e. the slot, as given to create(), returns or g_thread_exit() is called by the thread. (Calling g_thread_exit() in a C++ program should be avoided.) All resources of the thread including the Glib::Thread object are released. The thread must have been created with `joinable = true`.

## ◆ joinable()

bool Glib::Thread::joinable | ( |  | ) | const

Returns whether the thread is joinable.

Returns
  Whether the thread is joinable.

Deprecated:
  All threads are now joinable.

## ◆ operator=()

Thread& Glib::Thread::operator= | ( | const Thread & |  | ) |
| delete

## ◆ self()

static Thread* Glib::Thread::self | ( |  | ) |
| static

Returns the Thread* corresponding to the calling thread.

Returns
  The current thread.

## ◆ set_priority()

void Glib::Thread::set_priority | ( | ThreadPriority | priority | ) |

Changes the priority of the thread to priority.

Note
  It is not guaranteed, that threads with different priorities really behave accordingly. On some systems (e.g. Linux) only `root` can increase priorities. On other systems (e.g. Solaris) there doesn't seem to be different scheduling for different priorities. All in all try to avoid being dependent on priorities.

Parameters

  priority | A new priority for the thread.

Deprecated:
  Thread priorities no longer have any effect.

## ◆ yield()

static void Glib::Thread::yield | ( |  | ) |
| static

Gives way to other threads waiting to be scheduled.

This function is often used as a method to make busy wait less evil. But in most cases, you will encounter, there are better methods to do that. So in general you shouldn't use this function.

## Friends And Related Function Documentation

## ◆ wrap()

Thread * wrap | ( | GThread * | gobject | ) |
| related

Deprecated:
  Use Glib::Threads::wrap(GThread*) instead.