rpc_clnt_calls(3rpc)

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

Synopsis

cc [options] file -lnsl

#include <rpc/rcp.h>

enum clnt_stat clnt_call(CLIENT *clnt, const u_long procnum,
	const xdrproc_t inproc, caddr_t in, const xdrproc_t outproc,
	caddr_t out, const struct timeval tout);

int 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);

const char *clnt_sperrno(const enum clnt_stat stat);

char *clnt_sperror(const CLIENT *clnt, const char *s);

enum clnt_stat rpc_broadcast(const u_long prognum,
	const u_long versnum, const u_long procnum,
	const xdrproc_t inproc, caddr_t in, const xdrproc_t outproc,
	caddr_t out, const resultproc_t eachresult, const char *nettype);

enum clnt_stat rpc_broadcast_exp(const u_long prognum,
	const u_long versnum, const u_long procnum,
	const xdrproc_t inproc, caddr_t in, const xdrproc_t outproc,
	caddr_t out, const resultproc_t eachresult,
	int inittime, int waittime, const char *nettype);

enum clnt_stat rpc_call(const char *host, const u_long prognum,
	const u_long versnum, const u_long 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 data packet to the server. Upon receipt of the packet, the server calls a dispatch routine to perform the requested service, and then sends back a reply.

The clnt_call, rpc_call, rpc_broadcast, and rpc_broadcast_exp routines handle the client side of the procedure call. The remaining routines deal with error handling in the case of errors.

Routines

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

   enum clnt_stat
   clnt_call(CLIENT *clnt, const u_long procnum, const xdrproc_t inproc,
   	caddr_t in, const xdrproc_t outproc, caddr_t out,
   	const struct timeval tout);

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(3rpc)). The parameter in is the address of the procedure's argument(s), and out is the address of where to place the result(s); inproc is used to encode the procedure's parameters, and outproc is used to decode the procedure's results; tout is the time allowed for results to be returned.

If the remote call succeeds, the status is returned in RPC_SUCCESS, otherwise an appropriate status is returned.

int
clnt_freeres(CLIENT *clnt, const xdrproc_t outproc, caddr_t out);

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.

void
clnt_geterr(const CLIENT *clnt, struct rpc_err *errp);

A function macro that copies the error structure out of the client handle to the structure at address errp.

void
clnt_perrno(const enum clnt_stat stat);

Print a message to standard error corresponding to the condition indicated by stat. A newline is appended at the end of the message. Normally used after a procedure call fails, for instance rpc_call.

void
clnt_perror(const CLIENT *clnt, const char *s);

Print a message to 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 at the end of the message. Normally used after a procedure call fails, for instance clnt_call.

const char *
clnt_sperrno(const enum clnt_stat stat);

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 read-only 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 fprintf(3S)), 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(3rpc)), clnt_sperrno does not return pointer to static data so the result will not get overwritten on each call, and the string is read-only.

char *
clnt_sperror(const CLIENT *clnt, const char *s);

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.

Note: returns pointer to static data that is overwritten on each call.

enum clnt_stat
rpc_broadcast(const u_long prognum, const u_long versnum,
	const u_long procnum, const xdrproc_t inproc, caddr_t in,
	const xdrproc_t outproc, caddr_t out,
	const resultproc_t eachresult, const char *nettype);

enum clnt_stat
rpc_broadcast_exp(const u_long prognum, const u_long versnum,
	const u_long procnum, const xdrproc_t inproc, caddr_t in,
	const xdrproc_t outproc, caddr_t out,
	const resultproc_t eachresult, int inittime
	int waittime, const char *nettype);

These calls are like rpc_call, except the call message is broadcast to the connectionless network specified by nettype. If nettype is NULL, it defaults to netpath. rpc_broadcast simply calls rpc_broadcast_exp with inittime set to 4000 milliseconds and waittime set to 8000 milliseconds. Each time rpc_broadcast_exp receives a response, it calls eachresult, whose form is:

bool_t
eachresult(const caddr_t out, const struct netbuf *addr,
	struct netconfig *netconf);

where out is the same as out passed to rpc_broadcast and rpc_broadcast_exp except that the remote procedure's output is decoded in rpc_broadcast_exp; 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_exp and therefore rpc_broadcast wait for more replies; otherwise they return with appropriate status.

Note: broadcast file descriptors are limited in size to the maximum transfer size of that transport. For Ethernet, this value is 1500 bytes.

enum clnt_stat
rpc_call(const char *host, const u_long prognum,
	const u_long versnum, const u_long procnum,
	const xdrproc_t inproc, const char *in,
	const xdrproc_t outproc, char *out,
	const char *nettype);

Call the remote procedure associated with prognum, versnum, and procnum on the machine, host. The parameter in is the address of the procedure's argument(s), and out is the address of where to place the result(s); inproc is used to encode the procedure's parameters, and outproc is used to decode the procedure's results. nettype can be any of the values listed on rpc(3rpc). If nettype is NULL, it defaults to netpath. This routine returns 0 if it succeeds, or the value of enum clnt_stat cast to an integer if it fails. Use the clnt_perrno routine to translate failure statuses into messages.

Note: 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. There is also no way to destroy the client handle.

Files

/usr/lib/locale/locale/LC_MESSAGES/uxnsl

References

fprintf(3S), rpc(3rpc), rpc_clnt_auth(3rpc), rpc_clnt_create(3rpc)