rpc_clnt_calls(3)

NAME

rpc_clnt_calls, clnt_call, clnt_freeres, clnt_geterr,

clnt_perrno,
clnt_perror, clnt_sperrno, clnt_sperror, rpc_broadcast, rpc_broadcast_exp, rpc_call - library routines for client

side calls

LIBRARY

Standard C Library (libc, -lc)

SYNOPSIS

#include <rpc/rpc.h>
enum clnt_stat
clnt_call(CLIENT  *clnt,  const  rpcproc_t  procnum,   const
xdrproc_t inproc,
        const  caddr_t  in, const xdrproc_t outproc, caddr_t
out,
        const struct timeval tout);
bool_t
clnt_freeres(CLIENT *clnt, const xdrproc_t outproc,  caddr_t
out);
void
clnt_geterr(const CLIENT * clnt, struct rpc_err * errp);
void
clnt_perrno(const enum clnt_stat stat);
void
clnt_perror(CLIENT *clnt, const char *s);
char *
clnt_sperrno(const enum clnt_stat stat);
char *
clnt_sperror(CLIENT *clnt, const char * s);
enum clnt_stat
rpc_broadcast(const   rpcprog_t   prognum,  const  rpcvers_t
versnum,
        const rpcproc_t procnum, const xdrproc_t inproc,
        const caddr_t in, const xdrproc_t  outproc,  caddr_t
out,
        const resultproc_t eachresult, const char *nettype);
enum clnt_stat
rpc_broadcast_exp(const rpcprog_t prognum,  const  rpcvers_t
versnum,
        const  rpcproc_t  procnum,  const  xdrproc_t  xargs,
caddr_t argsp,
        const xdrproc_t xresults, caddr_t resultsp,
        const resultproc_t eachresult, const int inittime,
        const int waittime, const char * nettype);
enum clnt_stat
rpc_call(const char *host, const rpcprog_t prognum,
        const rpcvers_t versnum, const rpcproc_t procnum,
        const  xdrproc_t  inproc,  const  char  *in,   const
xdrproc_t outproc,
        char *out, const char *nettype);

DESCRIPTION

RPC library routines allow C language programs to make pro

cedure calls on
other machines across the network. First, the client calls

a procedure
to send a request to the server. Upon receipt of the re

quest, the server
calls a dispatch routine to perform the requested service,

and then sends
back a reply.

The clnt_call(), rpc_call(), and rpc_broadcast() routines

handle the
client side of the procedure call. The remaining routines

deal with
error handling in the case of errors.

Some of the routines take a CLIENT handle as one of the ar

guments. A
CLIENT handle can be created by an RPC creation routine such

as
clnt_create() (see rpc_clnt_create(3)).

These routines are safe for use in multithreaded applica

tions. CLIENT
handles can be shared between threads, however in this im

plementation
requests by different threads are serialized (that is, the

first request
will receive its results before the second request is sent).

Routines

See rpc(3) for the definition of the CLIENT data structure.

clnt_call()

A function macro that calls the remote procedure

procnum associated with the client handle, clnt, which is obtained

with an RPC
client creation routine such as clnt_create() (see rpc_clnt_create(3)). The inproc argument is the XDR

function used
to encode the procedure's arguments, and outproc is

the XDR function used to decode the procedure's results; in is

the address of
the procedure's argument(s), and out is the address

of where to
place the result(s). The tout argument is the time

allowed for
results to be returned, which is overridden by a

time-out set
explicitly through clnt_control(), see rpc_clnt_cre

ate(3). If the
remote call succeeds, the status returned is RPC_SUC

CESS, otherwise an appropriate status is returned.

clnt_freeres()

A function macro that frees any data allocated by the

RPC/XDR system when it decoded the results of an RPC call. The

out argument
is the address of the results, and outproc is the XDR

routine
describing the results. This routine returns 1 if

the results
were successfully freed, and 0 otherwise.

clnt_geterr()

A function macro that copies the error structure out

of the client
handle to the structure at address errp.

clnt_perrno()

Print a message to standard error corresponding to

the condition
indicated by stat. A newline is appended. Normally

used after a
procedure call fails for a routine for which a client

handle is
not needed, for instance rpc_call().

clnt_perror()

Print a message to the standard error indicating why

an RPC call
failed; clnt is the handle used to do the call. The

message is
prepended with string s and a colon. A newline is

appended. Normally used after a remote procedure call fails for a

routine which
requires a client handle, for instance clnt_call().

clnt_sperrno()

Take the same arguments as clnt_perrno(), but instead

of sending a
message to the standard error indicating why an RPC

call failed,
return a pointer to a string which contains the mes

sage. The
clnt_sperrno() function is normally used instead of

clnt_perrno()
when the program does not have a standard error (as a

program running as a server quite likely does not), or if the

programmer does
not want the message to be output with printf() (see

printf(3)),
or if a message format different than that supported

by
clnt_perrno() is to be used. Note: unlike

clnt_sperror() and
clnt_spcreateerror() (see rpc_clnt_create(3)),

clnt_sperrno() does
not return pointer to static data so the result will

not get overwritten on each call.

clnt_sperror()

Like clnt_perror(), except that (like clnt_sperrno())

it returns a
string instead of printing to standard error. Howev

er,
clnt_sperror() does not append a newline at the end

of the message. Warning: returns pointer to a buffer that is

overwritten on
each call.

rpc_broadcast()

Like rpc_call(), except the call message is broadcast

to all the
connectionless transports specified by nettype. If

nettype is
NULL, it defaults to "netpath". Each time it re

ceives a response,
this routine calls eachresult(), whose form is:

bool_t
eachresult(caddr_t out, const struct netbuf * addr,

const struct
netconfig * netconf) where out is the same as out

passed to
rpc_broadcast(), except that the remote procedure's

output is
decoded there; addr points to the address of the ma

chine that sent
the results, and netconf is the netconfig structure

of the transport on which the remote server responded. If

eachresult()
returns 0, rpc_broadcast() waits for more replies;

otherwise it
returns with appropriate status. Warning: broadcast

file descriptors are limited in size to the maximum transfer size

of that
transport. For Ethernet, this value is 1500 bytes.

The
rpc_broadcast() function uses AUTH_SYS credentials by

default (see
rpc_clnt_auth(3)).

rpc_broadcast_exp()

Like rpc_broadcast(), except that the initial time

out, inittime
and the maximum timeout, waittime are specified in

milliseconds.
The inittime argument is the initial time that

rpc_broadcast_exp()
waits before resending the request. After the first

resend, the
re-transmission interval increases exponentially un

til it exceeds
waittime.

rpc_call()

Call the remote procedure associated with prognum,

versnum, and
procnum on the machine, host. The inproc argument is

used to
encode the procedure's arguments, and outproc is used

to decode
the procedure's results; in is the address of the

procedure's
argument(s), and out is the address of where to place

the
result(s). The nettype argument can be any of the

values listed
on rpc(3). This routine returns RPC_SUCCESS if it

succeeds, or an
appropriate status is returned. Use the

clnt_perrno() routine to
translate failure status into error messages. Warn

ing: rpc_call()
uses the first available transport belonging to the

class nettype,
on which it can create a connection. You do not have

control of
timeouts or authentication using this routine.

SEE ALSO

printf(3), rpc(3), rpc_clnt_auth(3), rpc_clnt_create(3)

BSD May 7, 1993

BSD