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PKMESG(3PVM) PVM Version 3.4 PKMESG(3PVM)

NAME

pvm_pkmesg, pvm_pkmesgbody, pvm_upkmesg - Pack messages into other messages.

SYNOPSIS

C	int info = pvm_pkmesg( int bufid )


	int info = pvm_pkmesgbody( int bufid )


	int newbufid = pvm_upkmesg( )


Fortran	call pvmfpkmesg( bufid, info )
	call pvmfpkmesgbody( bufid, info )
	call pvmfupkmesg( bufid, newbufid )

PARAMETERS

Message buffer to pack.
New message buffer unpacked or result code.
Result code.

DESCRIPTION

These functions are used to include messages in other messages, as data elements.

pvm_pkmesg packs the specified message into the current send buffer. The entire body of the message is packed, along with header attributes:

	length
	context tag
	message tag
	wait identifier
	encoding
	checksum
	source and destination addresses
The buffer specified must not be the same as the current send buffer. Multiple messages can be packed into a single message, and packed messages can be mixed with any other data types.

pvm_upkmesg unpacks a message from the current receive buffer, allocating a new message buffer for it. The body of the newly created message, and header attributes listed above, match the one originally packed using pvm_pkmesg.

pvm_pkmesgbody is similar to pvm_pkmesg, but packs only the body of the specified message, omitting the header fields. In other words, it splices the messages together (the included message is left unaltered). When calling pvm_pkmesgbody, the encoding types of the two messages must match because the included message body is simply appended to the send buffer. Calls to pvm_pkmesgbody can be mixed with calls to pack any other data types.

Note: pvm_upkmesgbody doesn't exist, because PVM doesn't keep track of the boundary between the two messages.

EXAMPLES

	pvm_recv(-1, -1);
	pvm_initsend(PvmDataDefault);
	pvm_pkstr("here is the message I received...");
	pvm_pkmesg(pvm_getrbuf());

ERRORS

The following error conditions can be returned by pvm_pkmesg, pvm_pkmesgbody or pvm_upkmesg:

An invalid value was specified for bufid argument, or bufid is the current send buffer.
Message buffer bufid doesn't exist.
Libpvm is unable to allocate memory to pack data.
The end of the message has been reached, perhaps because pack and unpack calls were mismatched.
There is no current send (or receive) buffer.
pvm_pkmesgbody was called and the encoding types of bufid and the current send buffer don't match.

SEE ALSO

pvm_getrbuf(3PVM), pvm_getsbuf(3PVM), pvm_pack(3PVM),

10 February, 1995