Tizen Native API 5.5
These functions provide a wrapper that protect access to pointers.
Eina_Safepointer is an pointer to index converter that allows an increased level of safety by forbidding direct access to the pointer. The protection works by using a set of indirection tables that are mmapped and mprotected against write access. Thus the pointer they store and that map to a specific index is always correct. Also once a pointer is unregistered the index won't be served back for 2^8 on 32 bits system and 2^28 on 64 bits system for that specific slot. Finally we guarantee that the lower 2 bits of the returned index are actually never used and completely ignored by our API. So you can safely store whatever information you want in it, we will ignore it and treat as if it wasn't there.
- The use of Eina_Safepointer is thread safe.
|static void *||eina_safepointer_get (const Eina_Safepointer *safe)|
|Register a pointer and get an Eina_Safepointer that maps to it. |
|typedef struct _Eina_Safepointer||Eina_Safepointer|
Type of the protected index.
Register a pointer and get an Eina_Safepointer that maps to it.
[in] target The pointer to register.
- A valid pointer that is an index to the mapped pointer.
- It will return
NULLon error or if
- The lower 2 bits of the returned pointer will always be 0.
- The returned pointer can be used like a pointer, but cannot be touched except with Eina_Safepointer functions.
- Since (EFL) :
- 1.18 Unregister an Eina_Safepointer and the pointer that maps to it.
[in] safe The index to unregister from the mapping.
- This function will ignore the lower 2 bits of the given pointer.
- Since (EFL) :
- 1.18 Get the associated pointer from an Eina_Safepointer mapping.
[in] safe The Eina_Safepointer index to lookup at.
- The pointer registered with that index or
NULLin any other case.
- It is always safe to ask for a pointer for any value of the mapping. If the pointer is invalid or
NULL, we will return
NULLand not crash.