GETRENT(2) LAM NETWORK LIBRARY GETRENT(2)NAME
getrent, getrentc, getroute, getroute2, getrtype - Get LAM route
information.
C SYNOPSIS
#include <net.h>
#include <rreq.h>
#include <events.h>
int getrent (struct route *rent);
int getrentc (struct route *rent);
int getroute (struct nmsg *nhead);
int getroute2 (struct nmsg *nhead);
int getrtype (int nodeid);
FORTRAN SYNOPSIS
integer function IGRTP (nodeid)
integer nodeid
DESCRIPTION
These functions return information obtained from the local route dae‐
mon, a modular component of the LAM daemon. getrent() and getrentc()
accept a pointer to a route structure, defined in <rreq.h>:
struct route {
int r_nodeid;
int r_event;
int r_link;
int r_event2;
int r_link2;
int r_nodetype;
};
The structure fields hold the following information.
r_nodeid destination node ID
r_event forwarding event, representing the best suggested route to
the destination node
r_link forwarding link associated with r_event, if r_event is a
datalink output process
r_event2 secondary forwarding event, representing a non-reconvergent
route (primarily used for multicasting) with respect to
other destinations
r_link2 forwarding link associated with r_event2, if r_event2 is a
datalink output process
r_nodetype node type of destination node (see getntype(2))
getrent() sends a request for route information to the route daemon.
The r_nodeid field must be set by the caller to the nodeid of the des‐
tination node whose route table entry is required. All other fields
are filled by the function.
getrentc() has the exact functionality of getrent(), except that it
caches the recently accessed route table entries. Later access to the
same entries are faster. getrentc() first checks the cache for the
route entry of the given nodeid. If the entry is found, the requested
information is returned. Otherwise, getrent() is called, returning a
copy of the route table entry from the route daemon. This entry is
then stored in the cache.
The remaining functions are wrappers for getrentc(). getroute() ac‐
cepts a network message descriptor with the destination node and event
fields set and fills in the forwarding fields. getroute2() is similar
to getroute() except that the secondary routing information is used.
getrtype() accepts a node identifier and returns the type of that node.
C RETURN VALUE
Upon successful completion of getrent(), getrentc(), getroute(), or
getroute2(), 0 is returned. Otherwise, -1 is returned and global error
variable errno is set accordingly. getrtype() returns a valid node
type when successful. NOTNODETYPE (defined in <net.h>) is returned if
an error occurs. When an error occurs, these functions set the global
variable errno to the appropriate error code.
FORTRAN RETURN VALUEIGRTP() returns a valid node type when successful. NOTNODETYPE (see
CONSTANTS(5)) is returned if an error occurs.
ERRORS
EBADNODE The supplied node identifier does not exist.
SEE ALSOgetntype(2), rrsetrents(2), CONSTANTS(5)LAM 7.1.2 March, 2006 GETRENT(2)