Provided by: libtirpc-dev_1.3.4+ds-1.1build1_amd64 
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 operation, and info is a pointer to the information. For both
connectionless 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() immediately 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
indicates 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
default 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 registered with the rpcbind(8) service. This mismatch will be
discovered 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 availability. 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 successful it returns a client handle created for the highest version 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 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 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. Destruction usually involves
deallocation of private data structures, including clnt itself. Use of clnt is undefined after
calling clnt_destroy(). If the RPC library opened the associated 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 defaults. 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 instead of printing to the standard
error. A newline is not appended 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 messages 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 interference. 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-
oriented, 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
error 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
suitable defaults. Depending upon the type of the transport (connection-oriented or
connectionless), clnt_tli_create() calls appropriate 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 service.
clnt_tp_create()
Like clnt_create() except clnt_tp_create() tries only one transport 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 extra 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-oriented transport. The remote program is located at address svcaddr.
The fildes argument is an open and bound file descriptor. The user may specify the size of the
send and receive buffers 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 actual address of the remote program. The clnt_vc_create() function does
not consult the remote rpcbind service for this information.
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)
Debian May 7, 1993 RPC_CLNT_CREATE(3)