rpc_clnt_calls(3NSL) Networking Services Library Functionsrpc_clnt_calls(3NSL)NAME
rpc_clnt_calls, clnt_call, clnt_send, 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
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);
enum clnt_stat clnt_send (CLIENT *clnt, const u_long
procnum, const xdrproc_t proc, const caddr_t in);
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(const CLIENT *clnt, const char *s);
char *clnt_sperrno(const enum clnt_stat stat);
char *clnt_sperror(const CLIENT *clnt, const char *s);
enum clnt_stat rpc_broadcast(const rpcprog_t prognum,
const rpcvers_t versnum, const rpcproc_t procnum,
const xdrproc_tinproc, 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_txargs, caddr_t argsp, const xdrproc_txresults,
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 procedure calls
on other machines across the network. First, the client calls a proce‐
dure to send a request to the server. Upon receipt of the request, 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.
Some of the routines take a CLIENT handle as one of the parameters. A
CLIENT handle can be created by an RPC creation routine such as
clnt_create(). See rpc_clnt_create(3NSL).
These routines are safe for use in multithreaded applications. CLIENT
handles can be shared between threads; however, in this implementation
requests by different threads are serialized. In other words, the first
request will receive its results before the second request is sent.
Routines
See rpc(3NSL) 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_cre‐
ate(3NSL). The parameter inproc is the XDR
function used to encode the procedure's parame‐
ters, 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).
tout is the time allowed for results to be
returned, which is overridden by a time-out set
explicitly through clnt_control(). See
rpc_clnt_create(3NSL).
If the remote call succeeds, the status returned
is RPC_SUCCESS. Otherwise, an appropriate status
is returned.
clnt_send() Use the clnt_send() function to call a remote
asynchronous function.
The clnt_send() function calls the remote func‐
tion procnum() associated with the client han‐
dle, clnt, which is obtained with an RPC client
creation routine such as clnt_create(). See
rpc_clnt_create(3NSL). The parameter proc is the
XDR function used to encode the procedure's
parameters. The parameter in is the address of
the procedure's argument(s).
By default, the blocking I/O mode is used. See
the clnt_control(3NSL) man page for more infor‐
mation on I/O modes.
The clnt_send() function does not check if the
program version number supplied to clnt_create()
is registered with the rpcbind service. Use
clnt_create_vers() instead of clnt_create() to
check on incorrect version number registration.
clnt_create_vers() will return a valid handle to
the client only if a version within the range
supplied to clnt_create_vers() is supported by
the server.
RPC_SUCCESS is returned when a request is suc‐
cessfully delivered to the transport layer. This
does not mean that the request was received. If
an error is returned, use the clnt_getterr()
routine to find the failure status or the
clnt_perrno() routine to translate the failure
status into error messages.
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 parameter out 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; otherwise it returns 0.
clnt_geterr() A function macro that copies the error structure
out of the client handle to the structure at
address errp.
clnt_perrno() Prints a message to standard error corresponding
to the condition indicated by stat. A newline is
appended. It is normally used after a procedure
call fails for a routine for which a client han‐
dle is not needed, for instance rpc_call()clnt_perror() Prints a message to the standard error indicat‐
ing 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. This routine is normally used after a
remote procedure call fails for a routine that
requires a client handle, for instance
clnt_call().
clnt_sperrno() Takes the same arguments as clnt_perrno(), but
instead of sending a message to the standard
error indicating why an RPC call failed, returns
a pointer to a string that contains the message.
clnt_sperrno() 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. clnt_sperrno() is also
used if the programmer does not want the message
to be output with printf(), or if a message for‐
mat different than that supported by clnt_per‐
rno() is to be used. See printf(3C). Unlike
clnt_sperror() and clnt_spcreaterror(),
clnt_sperrno() does not return a pointer to
static data. Therefore, the result is not over‐
written on each call. See rpc_clnt_create(3NSL).
clnt_sperror() Similar to clnt_perror(), except that like
clnt_sperrno(), it returns a string instead of
printing to standard error. However, clnt_sper‐
ror() does not append a newline at the end of
the message.
clnt_sperror() returns a pointer to a buffer
that is overwritten on each call. In multi‐
threaded applications, this buffer is imple‐
mented as thread-specific data.
rpc_broadcast() Similar to rpc_call(), except that the call mes‐
sage is broadcast to all the connectionless
transports specified by nettype. If nettype is
NULL, it defaults to netpath. Each time it
receives a response, this routine calls eachre‐
sult(), 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 proce‐
dure's output is decoded there. addr points to
the address of the machine that sent the
results, and netconf is the netconfig structure
of the transport on which the remote server
responded. If eachresult() returns 0, rpc_broad‐
cast() waits for more replies; otherwise, it
returns with appropriate status.
The broadcast file descriptors are limited in
size to the maximum transfer size of that trans‐
port. For Ethernet, this value is 1500 bytes.
rpc_broadcast() uses AUTH_SYS credentials by
default. See rpc_clnt_auth(3NSL).
rpc_broadcast_exp() Similar to rpc_broadcast(), except that the ini‐
tial timeout, inittime and the maximum timeout,
waittime, are specified in milliseconds.
inittime is the initial time that rpc_broad‐
cast_exp() waits before resending the request.
After the first resend, the retransmission
interval increases exponentially until it
exceeds waittime.
rpc_call() Calls the remote procedure associated with
prognum, versnum, and procnum on the machine,
host. The parameter inproc is used to encode the
procedure's parameters, 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).
nettype can be any of the values listed on
rpc(3NSL). This routine returns RPC_SUCCESS if
it succeeds, or it returns an appropriate sta‐
tus. Use the clnt_perrno() routine to translate
failure status into error messages.
The rpc_call() function 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.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Architecture │All │
├─────────────────────────────┼─────────────────────────────┤
│Availability │system/library (32-bit) │
├─────────────────────────────┼─────────────────────────────┤
│ │SUNWcslx (64-bit) │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Committed │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOprintf(3C), rpc(3NSL), rpc_clnt_auth(3NSL), rpc_clnt_create(3NSL),
attributes(5)SunOS 5.11 1 Aug 2001 rpc_clnt_calls(3NSL)