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 char
*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(
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_t inproc,
const char *in,
const xdrproc_t outproc,
caddr_t out,
const resultproc_t
eachresult,
const char
*nettype);
enum clnt_stat
rpc_broadcast_exp(
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 int inittime,
const int waittime,
const resultproc_t
eachresult,
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 procedure 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 in the case of
errors.
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(3)).
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 (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 parameter inproc() is the XDR function used to
encode the procedure's parameters, 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(3).
If the remote call succeeds, the status returned is
RPC_SUCCESS
, 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 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, 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 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), 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_spcreaterror() (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. However, 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 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. Warning: 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(3)).
-
-
- rpc_broadcast_exp()
- Like rpc_broadcast(), except that the
initial timeout, inittime and the maximum timeout,
waittime are specified in milliseconds.
inittime is the initial time that
rpc_broadcast_exp() waits before resending the request.
After the first resend, the re-transmission interval increases
exponentially until it exceeds waittime.
-
-
- rpc_call()
- Call 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(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. Warning: 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)