getpmsg System Call

Communications Technical Reference, Volume 2

getpmsg System Call

Purpose

Gets the next priority message off a stream.

Syntax

#include <stropts.h>

int getpmsg (fd, ctlptr, dataptr, bandp, flags)
int fd;
struct strbuf *ctlptr;
struct strbuf *dataptr;
int *bandp;
int *flags;

Description

The getpmsg system call is identical to the getmsg system call, except that the message priority can be specified.

Parameters

Specifies a file descriptor referencing an open stream.

ctlptr

Holds the control part of the message.

dataptr

Holds the data part of the message.

bandp

Specifies the priority band of the message. If the value of the bandp parameter is set to 0, then the priority band is not limited.

flags

Indicates the type of message priority to be retrieved. Acceptable values are:

MSG_ANY	Process the next message of any type.
MSG_BAND	Process the next message only if it is of the specified priority band.
MSG_HIPRI	Process the next message only if it is a priority message.

If the value of the flags parameter is MSG_ANY or MSG_HIPRI, then the bandp parameter must be set to 0.

Implementation Specifics

This system call is part of the STREAMS Kernel Extensions.

Related Information

The poll subroutine, read subroutine, write subroutine.

The getmsg system call, putmsg system call, putpmsg system call.

List of Streams Programming References and STREAMS Overview in AIX Version 4.3 Communications Programming Concepts, and X/OPEN Common Application Environment (CAE) Specification: System Interfaces and Headers, Issue 5 (2/97).