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document better how SingletonRef works

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This commit is contained in:
Fischlurch 2009-11-07 17:37:37 +01:00
parent 0ed30225b6
commit 6dbbc54247
1 changed files with 14 additions and 2 deletions
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16
src/lib/singleton-ref.hpp
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@ -23,7 +23,15 @@
/** @file singleton-ref.hpp
** Helper for singleton-kind access without managing object creation and lifecycle.
** A typical usage scenario is when implementing C Language Interfaces without any
** canonical access to some "this" pointer.
** canonical access to some "this" pointer. In this case
** - an instance of the \c Access policy class is created "somewhere" (usually as
** global variable). Calls from within the C code would enter through this accessor.
** - when the actual service implementation class comes up, it creates an SingletonRef
** instance and thereby wires the (already existing) accessor up with \c *this
** - when the service goes down, access is closed automatically and reliably.
** Client code (from within C) should check the accessor (by \c bool check)
** prior to any access, because accessing a closed connection will throw
** (that's unfortunate, but at least throwing is better than segfaulting)
**
** @see gui::NotificationService usage example
*/
@ -90,7 +98,11 @@ namespace lib {
/*************************************************************
* Helper template providing singleton access without managing
* object creation and lifecycle.
* object creation and lifecycle. Just the access to the
* implementation instance is handled: on creation, access is
* enabled, and disabled on destruction. Client code is assumed
* to invoke through the Access (template template param),
* handed in as ctor parameter.
* @param TY the actual type to be made accessible
* @param B a base class to inherit from; defaults to noncopyable
* @param Accessor how to implement the static instance access