nsISupports

Table of contents

  1. 1. Method overview
  2. 2. Methods
    1. 2.1. AddRef()
    2. 2.2. QueryInterface()
    3. 2.3. Release()
  3. 3. Remarks
Page Notifications Off

All XPCOM interfaces inherit this interface.
 Last changed in Gecko 1.0

Method overview

nsrefcnt AddRef();Violates the xpcom interface guidelines!
void QueryInterface(in nsIIDRef uuid, [iid_is(uuid),retval] out nsQIResult result);
nsrefcnt Release();Violates the xpcom interface guidelines!

Methods

Violates the xpcom interface guidelines!

AddRef()

Notifies the object that an interface pointer has been duplicated.

nsrefcnt AddRef();
Parameters

None.

Return value

An integer value that is generally ignored.

QueryInterface()

The QueryInterface method provides runtime type discovery.

Note: The interface pointer, aResult, returned by QueryInterface must be released by a call to Release() when it is no longer needed. QueryInterface is a symmetric, transitive, and reflexive operator.

void QueryInterface(
  in nsIIDRef uuid,
  [iid_is(uuid),retval] out nsQIResult result
);
Parameters
uuid
The uuid of the requested interface
result
The resulting interface pointer.
Exceptions thrown
NS_ERROR_NO_INTERFACE
The requested interface is not available.

Violates the xpcom interface guidelines!

Release()

Notifies the object that an interface pointer has been destroyed and any resources the object held on behalf of the client can be released.

nsrefcnt Release();
Parameters

None.

Return value

An integer value that is generally ignored.

Remarks

The method descriptions above were taken from Essential COM by Don Box. The point of those descriptions is to highlight the fact that AddRef() and Release() do not necessarily correspond to incrementing and decrementing a counter, respectively, even though that is how they are usually implemented.

On Win32 systems, nsISupports is ABI-compatible with Microsoft COM's IUnknown interface.

Tags (4)

Edit tags

Attachments (0)

 

Attach file