RPC_CLNT_CALLS(3) BSD Library Functions Manual 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 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 arguments. 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 associ‐
ated 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 func‐
tion 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_create(3). If the
remote call succeeds, the status returned is RPC_SUCCESS, other‐
wise an appropriate status is returned.
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 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. Nor‐
mally 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. The
clnt_sperrno() function is normally used instead of clnt_perrno()
when the program does not have a standard error (as a program run‐
ning 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 over‐
written 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 mes‐
sage. 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 trans‐
port 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 descrip‐
tors 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 timeout, 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 until 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. 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 ALSOprintf(3), rpc(3), rpc_clnt_auth(3), rpc_clnt_create(3)BSD May 7, 1993 BSD
