ck Namespace Reference

The class envelope defines a Charm++ message's header. More...

Data Structures
class	ArrayIndexCompressor
class	FixedArrayIndexCompressor
class	ObjID
	The basic element identifier. More...
Namespaces
namespace	impl
Functions
bool	operator== (ObjID lhs, ObjID rhs)
bool	operator!= (ObjID lhs, ObjID rhs)

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Detailed Description

The class envelope defines a Charm++ message's header.

The first 'CmiReservedHeaderSize' bytes of memory is exclusively reserved for Converse header, which is defined in converse.h and platform specific config files.

After Charm++ envelope comes the payload, i.e. a variable-length amount of user data. Following the user data, optionally, a variable number of bits of priority data can be stored at the end. Function envelope::alloc(msgtype,size,prio) is always used to allocate the whole message. Note that this memory layout must be observed.

The following are a few terms that are used often:

 Envelope pointer        \
 Converse message pointer -> [ [ Converse envelope ]       ]
                             [       Charm envelope        ] 
 User message pointer     -> [ User data/payload ... ]
 Priority pointer         -> [ Priority ints ... ]

The "message pointers" passed to and from users bypass the envelope and point directly* to the user data--the routine "EnvToUsr" below adjusts an envelope (or converse message) pointer into this user message pointer. There is a corresponding routine "UsrToEnv" which takes the user data pointer and returns a pointer to the envelope/converse message.

Unfortunately, in the guts of Charm++ it's not always clear whether you've been given a converse or user message pointer, as both tend to be passed as void *. Confusing the two will invariably result in data corruption and bizarre crashes.

FIXME: Make CkMessage inherit from envelope, which would unify converse, envelope, and user message pointers.

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Function Documentation

bool ck::operator==	(	ObjID	lhs,
		ObjID	rhs
	)			[inline]

Definition at line 87 of file objid.h.

References ck::ObjID::getID().

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bool ck::operator!=	(	ObjID	lhs,
		ObjID	rhs
	)			[inline]

Definition at line 90 of file objid.h.