CHandle

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Revision as of 10:48, 9 June 2009 by TomEdwards (talk | contribs) (CHandles are slower than pointers)
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CHandle is a C++ class that represents a 32-bit ID (entindex + serial number) unique to every past and present entity in a game. It is used to refer to entities where pointers and entity indexes are unsafe; mainly across the client/server divide and after restoring a saved game.

Tip.pngTip:CHandles are considerably slower to access than pointers. If you do create any pointers, and are supporting saved games, remember to repopulate them in Restore()!

Usage

CHandle<YourStoredClass> hMyHandle;

A CHandle is broadly similar to a pointer, but as it is a standard C++ class extra syntax is needed in some places:

  • You must assign a pointer to an object, not the object itself
  • Get() or a cast is required access the class it is storing
  • IsValid() is required to check whether a value is stored
  • To invalidate, call Term() or assign INVALID_EHANDLE_INDEX.

EHANDLE

CHandle is often used through the EHANDLE typedef, which is shorthand for CHandle<C_BaseEntity>. If you want to store a particular class it's better to declare a more specific CHandle manually (see previous section).

Example

// Create a pointer to an entity
CBasePlayer* pPlayer = gEntList.FindEntityByClassname( NULL, "player" );
 
// Store it (twice, for demonstration purposes)
EHANDLE hPlayer = pPlayer;
CHandle<CBasePlayer> hPlayer_ = pPlayer;
 
// Convert the EHANDLE back to a CBasePlayer pointer
pPlayer = dynamic_cast<CBasePlayer*>( hPlayer.Get() );

See Also