class: Mutex

[29:7] extends: object

The #GMutex struct is an opaque data structure to represent a mutex (mutual exclusion). It can be used to protect data against shared access. Take for example the following function: |[ int give_me_next_number (void) { static int current_number = 0; // now do a very complicated calculation to calculate the new // number, this might for example be a random number generator current_number = calc_next_number (current_number); return current_number; } ]| It is easy to see that this won't work in a multi-threaded application. There current_number must be protected against shared access. A #GMutex can be used as a solution to this problem: |[ int give_me_next_number (void) { static GMutex mutex; static int current_number = 0; int ret_val; g_mutex_lock (&mutex); ret_val = current_number = calc_next_number (current_number); g_mutex_unlock (&mutex); return ret_val; } ]| Notice that the #GMutex is not initialised to any particular value. Its placement in static storage ensures that it will be initialised to all-zeros, which is appropriate. If a #GMutex is placed in other contexts (eg: embedded in a struct) then it must be explicitly initialised using g_mutex_init(). A #GMutex should only be accessed via g_mutex_ functions.

Members

• handleObj
• lib
• retainedCallbacks
• signalHandlerNames
• signalSetterHandlers

Methods

• Mutex (Handle = null)

  Creates a new Mutex by wrapping a native handle or another wrapper.

  • @p Handle is the native handle or another wrapper whose handle to adopt.

• toNativeHandle (Source)

  Normalizes a constructor argument into a raw pointer carrier. Accepts a raw NativeHandle, a raw NativeBuffer returned from fn.call(...), another generated wrapper exposing handle(), or null. Returns null when the argument carries no pointer.

  • @p Source is the raw handle, raw buffer, wrapper, or null.
  • @r A raw pointer carrier or null when no pointer is present.

• getLib ()

  Returns the opened native library for this generated wrapper.

  • @r The opened native library.

• handle ()

  Returns the wrapped NativeHandle.

  • @r The wrapped NativeHandle.

• isNull ()

  Returns true when the wrapped handle is null.

  • @r A bool.

• describe ()

  Returns a small string for debugging generated wrappers.

  • @r A string.