RPC_CLNT_CREATE(3) BSD Library Functions Manual RPC_CLNT_CREATE(3)
NAME
rpc_clnt_create, clnt_control, clnt_create, clnt_create_timed,
clnt_create_vers, clnt_create_vers_timed, clnt_destroy, clnt_dg_create,
clnt_pcreateerror, clnt_raw_create, clnt_spcreateerror, clnt_tli_create,
clnt_tp_create, clnt_tp_create_timed, clnt_vc_create, rpc_createerr --
library routines for dealing with creation and manipulation of CLIENT
handles
SYNOPSIS
#include <rpc/rpc.h>
bool_t
clnt_control(CLIENT *clnt, const u_int req, char *info);
CLIENT *
clnt_create(const char * host, const rpcprog_t prognum,
const rpcvers_t versnum, const char *nettype);
CLIENT *
clnt_create_timed(const char * host, const rpcprog_t prognum,
const rpcvers_t versnum, const char *nettype,
const struct timeval *timeout);
CLIENT *
clnt_create_vers(const char * host, const rpcprog_t prognum,
rpcvers_t *vers_outp, const rpcvers_t vers_low,
const rpcvers_t vers_high, const char *nettype);
CLIENT *
clnt_create_vers_timed(const char * host, const rpcprog_t prognum,
rpcvers_t *vers_outp, const rpcvers_t vers_low,
const rpcvers_t vers_high, char *nettype,
const struct timeval *timeout);
void
clnt_destroy(CLIENT *clnt);
CLIENT *
clnt_dg_create(const int fildes, const struct netbuf *svcaddr,
const rpcprog_t prognum, const rpcvers_t versnum, const u_int sendsz,
const u_int recvsz);
void
clnt_pcreateerror(const char *s);
char *
clnt_spcreateerror(const char *s);
CLIENT *
clnt_raw_create(const rpcprog_t prognum, const rpcvers_t versnum);
CLIENT *
clnt_tli_create(const int fildes, const struct netconfig *netconf,
const struct netbuf *svcaddr, const rpcprog_t prognum,
const rpcvers_t versnum, const u_int sendsz, const u_int recvsz);
CLIENT *
clnt_tp_create(const char * host, const rpcprog_t prognum,
const rpcvers_t versnum, const struct netconfig *netconf);
CLIENT *
clnt_tp_create_timed(const char * host, const rpcprog_t prognum,
const rpcvers_t versnum, const struct netconfig *netconf,
const struct timeval *timeout);
CLIENT *
clnt_vc_create(const int fildes, const struct netbuf *svcaddr,
const rpcprog_t prognum, const rpcvers_t versnum, u_int sendsz,
u_int recvsz);
DESCRIPTION
RPC library routines allow C language programs to make procedure calls on
other machines across the network. First a CLIENT handle is created and
then the client calls a procedure to send a request to the server. On
receipt of the request, the server calls a dispatch routine to perform
the requested service, and then sends a reply.
Routines
clnt_control()
A function macro to change or retrieve various information about
a client object. The req argument indicates the type of opera-
tion, and info is a pointer to the information. For both con-
nectionless and connection-oriented transports, the supported
values of req and their argument types and what they do are:
CLSET_TIMEOUT struct timeval * set total timeout
CLGET_TIMEOUT struct timeval * get total timeout
Note: if you set the timeout using clnt_control(), the timeout
argument passed by clnt_call() is ignored in all subsequent
calls.
Note: If you set the timeout value to 0, clnt_control() immedi-
ately returns an error (RPC_TIMEDOUT). Set the timeout argument
to 0 for batching calls.
CLGET_SVC_ADDR struct netbuf * get servers address
CLGET_FD int * get fd from handle
CLSET_FD_CLOSE void close fd on destroy
CLSET_FD_NCLOSE void don't close fd on destroy
CLGET_VERS u_int32_t * get RPC program version
CLSET_VERS u_int32_t * set RPC program version
CLGET_XID u_int32_t * get XID of previous call
CLSET_XID u_int32_t * set XID of next call
The following operations are valid for connectionless transports
only:
CLSET_RETRY_TIMEOUT struct timeval * set the retry timeout
CLGET_RETRY_TIMEOUT struct timeval * get the retry timeout
CLSET_CONNECT int * use connect(2)
The retry timeout is the time that RPC waits for the server to
reply before retransmitting the request. The clnt_control()
function returns TRUE on success and FALSE on failure.
clnt_create()
Generic client creation routine for program prognum and version
versnum. The host argument identifies the name of the remote
host where the server is located. The nettype argument indi-
cates the class of transport protocol to use. The transports
are tried in left to right order in NETPATH environment variable
or in top to bottom order in the netconfig database. The
clnt_create() function tries all the transports of the nettype
class available from the NETPATH environment variable and the
netconfig database, and chooses the first successful one. A de-
fault timeout is set and can be modified using clnt_control().
This routine returns NULL if it fails. The clnt_pcreateerror()
routine can be used to print the reason for failure.
Note: clnt_create() returns a valid client handle even if the
particular version number supplied to clnt_create() is not reg-
istered with the rpcbind(8) service. This mismatch will be dis-
covered by a clnt_call() later (see rpc_clnt_calls(3)).
clnt_create_timed()
Generic client creation routine which is similar to
clnt_create() but which also has the additional argument timeout
that specifies the maximum amount of time allowed for each
transport class tried. In all other respects, the
clnt_create_timed() call behaves exactly like the clnt_create()
call.
clnt_create_vers()
Generic client creation routine which is similar to
clnt_create() but which also checks for the version availabil-
ity. The host argument identifies the name of the remote host
where the server is located. The nettype argument indicates the
class transport protocols to be used. If the routine is suc-
cessful it returns a client handle created for the highest ver-
sion between vers_low and vers_high that is supported by the
server. The vers_outp argument is set to this value. That is,
after a successful return vers_low <= *vers_outp <= vers_high.
If no version between vers_low and vers_high is supported by the
server then the routine fails and returns NULL. A default time-
out is set and can be modified using clnt_control(). This rou-
tine returns NULL if it fails. The clnt_pcreateerror() routine
can be used to print the reason for failure. Note:
clnt_create() returns a valid client handle even if the particu-
lar version number supplied to clnt_create() is not registered
with the rpcbind(8) service. This mismatch will be discovered
by a clnt_call() later (see rpc_clnt_calls(3)). However,
clnt_create_vers() does this for you and returns a valid handle
only if a version within the range supplied is supported by the
server.
clnt_create_vers_timed()
Generic client creation routine which is similar to
clnt_create_vers() but which also has the additional argument
timeout that specifies the maximum amount of time allowed for
each transport class tried. In all other respects, the
clnt_create_vers_timed() call behaves exactly like the
clnt_create_vers() call.
clnt_destroy()
A function macro that destroys the client's RPC handle. De-
struction usually involves deallocation of private data struc-
tures, including clnt itself. Use of clnt is undefined after
calling clnt_destroy(). If the RPC library opened the associ-
ated file descriptor, or CLSET_FD_CLOSE was set using
clnt_control(), the file descriptor will be closed. The caller
should call auth_destroy(clnt->cl_auth) (before calling
clnt_destroy()) to destroy the associated AUTH structure (see
rpc_clnt_auth(3)).
clnt_dg_create()
This routine creates an RPC client for the remote program
prognum and version versnum; the client uses a connectionless
transport. The remote program is located at address svcaddr.
The fildes argument is an open and bound file descriptor. This
routine will resend the call message in intervals of 15 seconds
until a response is received or until the call times out. The
total time for the call to time out is specified by clnt_call()
(see clnt_call() in rpc_clnt_calls(3)). The retry time out and
the total time out periods can be changed using clnt_control().
The user may set the size of the send and receive buffers with
the sendsz and recvsz arguments; values of 0 choose suitable de-
faults. This routine returns NULL if it fails.
clnt_pcreateerror()
Print a message to standard error indicating why a client RPC
handle could not be created. The message is prepended with the
string s and a colon, and appended with a newline.
clnt_spcreateerror()
Like clnt_pcreateerror(), except that it returns a string in-
stead of printing to the standard error. A newline is not ap-
pended to the message in this case. Warning: returns a pointer
to a buffer that is overwritten on each call.
clnt_raw_create()
This routine creates an RPC client handle for the remote program
prognum and version versnum. The transport used to pass mes-
sages to the service is a buffer within the process's address
space, so the corresponding RPC server should live in the same
address space; (see svc_raw_create() in rpc_svc_create(3)).
This allows simulation of RPC and measurement of RPC overheads,
such as round trip times, without any kernel or networking in-
terference. This routine returns NULL if it fails. The
clnt_raw_create() function should be called after
svc_raw_create().
clnt_tli_create()
This routine creates an RPC client handle for the remote program
prognum and version versnum. The remote program is located at
address svcaddr. If svcaddr is NULL and it is connection-ori-
ented, it is assumed that the file descriptor is connected. For
connectionless transports, if svcaddr is NULL, RPC_UNKNOWNADDR
error is set. The fildes argument is a file descriptor which
may be open, bound and connected. If it is RPC_ANYFD, it opens
a file descriptor on the transport specified by netconf. If
fildes is RPC_ANYFD and netconf is NULL, a RPC_UNKNOWNPROTO er-
ror is set. If fildes is unbound, then it will attempt to bind
the descriptor. The user may specify the size of the buffers
with the sendsz and recvsz arguments; values of 0 choose suit-
able defaults. Depending upon the type of the transport (con-
nection-oriented or connectionless), clnt_tli_create() calls ap-
propriate client creation routines. This routine returns NULL
if it fails. The clnt_pcreateerror() routine can be used to
print the reason for failure. The remote rpcbind service (see
rpcbind(8)) is not consulted for the address of the remote ser-
vice.
clnt_tp_create()
Like clnt_create() except clnt_tp_create() tries only one trans-
port specified through netconf. The clnt_tp_create() function
creates a client handle for the program prognum, the version
versnum, and for the transport specified by netconf. Default
options are set, which can be changed using clnt_control()
calls. The remote rpcbind service on the host host is consulted
for the address of the remote service. This routine returns
NULL if it fails. The clnt_pcreateerror() routine can be used
to print the reason for failure.
clnt_tp_create_timed()
Like clnt_tp_create() except clnt_tp_create_timed() has the ex-
tra argument timeout which specifies the maximum time allowed
for the creation attempt to succeed. In all other respects, the
clnt_tp_create_timed() call behaves exactly like the
clnt_tp_create() call.
clnt_vc_create()
This routine creates an RPC client for the remote program
prognum and version versnum; the client uses a connection-ori-
ented transport. The remote program is located at address
svcaddr. The fildes argument is an open and bound file descrip-
tor. The user may specify the size of the send and receive buf-
fers with the sendsz and recvsz arguments; values of 0 choose
suitable defaults. This routine returns NULL if it fails. The
address svcaddr should not be NULL and should point to the ac-
tual address of the remote program. The clnt_vc_create() func-
tion does not consult the remote rpcbind service for this infor-
mation.
struct rpc_createerr rpc_createerr;
A global variable whose value is set by any RPC client handle
creation routine that fails. It is used by the routine
clnt_pcreateerror() to print the reason for the failure.
AVAILABILITY
These functions are part of libtirpc.
SEE ALSO
rpc(3), rpc_clnt_auth(3), rpc_clnt_calls(3), rpcbind(8)
BSD May 7, 1993 BSD