HP-UX Multimedia Streaming Protocols (MSP) Programmer's Guide

Table 2-1 The option Values (continued)
DescriptionValue
Request to join the multicast group to
receive multicast RTP packets on the
RTP session descriptor.
RTP_AMCAST (struct ip_mreq *mreq)
Request to join the multicast group to
receive multicast RTCP packets on the
RTP session descriptor.
RTCP_AMCAST (struct ip_mreq *mreq)
For more information, type man 3n rtp_ioctl at the HP-UX command prompt.
Monitoring RTP and RTCP I/O Conditions
The RTP library provides a general mechanism for reporting I/O conditions associated
with a set of RTP descriptors and for waiting until one or more specified conditions
become true. Specified I/O conditions include the ability to read or write data without
blocking and error conditions.
These APIs use the rtp_poll_t or the rtcp_poll_t data structure, as follows, to
poll the I/O conditions for a set of RTP session descriptors:
struct rtp_pollrd {
int rd; /* rtp descriptor */
short events; /* Requested conditions */
short revents; /* Reported conditions */};
typedef struct rtp_pollrd rtp_pollrd_t;
typedef struct rtp_pollrd rtcp_pollrd_t;
The APIs that monitor RTP or RTCP I/O conditions arertp_poll and rtcp_poll. In
effect, rtp_poll or rtcp_poll polls the RTP/RTCP port for the availability of an
RTP/RTCP packet for reading.
The declarations of rtp_poll and rtcp_poll are as follows:
# include <rtp.h>
int rtp_poll(rtp_pollrd_t [], int nfds, int timeout);
# include <rtp.h>
int rtcp_poll(rtp_pollrd_t [], int nfds, int timeout);
The rtp_poll API also examines the ability of the RTP port to take in another RTP
packet for transmission. This is not applicable to RTCP, as the library initiates the
transmission of non-BYE RTCP packets and the BYE RTCP packet in a few cases, such
as collision of SSRC.
Other APIs
The following lists the other APIs that the RTP library includes:
RTP Library 25