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 eachre‐
sult, 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 result‐
proc_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_create(3NSL).
The parameter inproc is the XDR function used to encode the proce‐
dure's parameters, and outproc is the XDR function used to decode
the procedure's results. in is the address of the procedure's argu‐
ment(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 over‐
ridden 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 func‐
tion.
The clnt_send() function calls the remote function procnum() asso‐
ciated 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 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_con‐
trol(3NSL) man page for more information on I/O modes.
The clnt_send() function does not check if the program version num‐
ber supplied to clnt_create() is registered with the rpcbind ser‐
vice. 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 successfully 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 trans‐
late the failure status into error messages.
clnt_freeres()
A function macro that frees any data allocated by the RPC/XDR sys‐
tem 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 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. 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 format different than that supported by clnt_perrno()
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 overwritten 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_sperror() does not append a <newline> at the end of the mes‐
sage.
clnt_sperror() returns a pointer to a buffer that is overwritten on
each call. In multithreaded applications, this buffer is imple‐
mented as thread-specific data.
rpc_broadcast()
Similar to rpc_call(), except that the call message 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 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 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_broadcast() 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 transport. 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 initial timeout, init‐
time and the maximum timeout, waittime, are specified in millisec‐
onds.
inittime is the initial time that rpc_broadcast_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 argu‐
ment(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
status. Use the clnt_perrno() routine to translate failure status
into error messages.
The rpc_call() function uses the first available transport belong‐
ing to the class nettype on which it can create a connection. You
do not have control of timeouts or authentication using this rou‐
tine.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
┌─────────────────────────────┬─────────────────────────────┐
│ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
├─────────────────────────────┼─────────────────────────────┤
│Architecture │All │
├─────────────────────────────┼─────────────────────────────┤
│Availability │SUNWcsl (32-bit) │
├─────────────────────────────┼─────────────────────────────┤
│ │SUNWcslx (64-bit) │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Evolving │
├─────────────────────────────┼─────────────────────────────┤
│MT-Level │MT-Safe │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOprintf(3C), rpc(3NSL), rpc_clnt_auth(3NSL), rpc_clnt_create(3NSL),
attributes(5)SunOS 5.10 1 Aug 2001 rpc_clnt_calls(3NSL)
