Simple messages

QNX SDP8.0System ArchitectureDeveloperUser

For simple single-part messages, the OS provides functions that take a pointer directly to a buffer without the need for an IOV (input/output vector). In this case, the number of parts is replaced by the size of the message directly pointed to.

In the case of the message send primitive—which takes a send and a reply buffer—this introduces four variations:
Function Send message Reply message
MsgSend() Simple Simple
MsgSendsv() Simple IOV
MsgSendvs() IOV Simple
MsgSendv() IOV IOV
The other messaging primitives that take a direct message simply drop the trailing v in their names:
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