RPC_CLNT_CREATE(3) | 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 handlesLIBRARY¶
Standard C Library (libc, -lc)SYNOPSIS¶
#include <rpc/rpc.h> bool_tclnt_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 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 CLSET_RETRY_TIMEOUT
struct timeval * set the retry timeout CLGET_RETRY_TIMEOUT
struct timeval * get the retry timeout CLSET_CONNECT
int * use connect(2) TRUE
on success andFALSE
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 theNETPATH
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 returnsNULL
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 returnsNULL
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 isNULL
,RPC_UNKNOWNADDR
error is set. The fildes argument is a file descriptor which may be open, bound and connected. If it isRPC_ANYFD
, it opens a file descriptor on the transport specified by netconf. If fildes isRPC_ANYFD
and netconf isNULL
, aRPC_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 returnsNULL
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 beNULL
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.
SEE ALSO¶
rpc(3), rpc_clnt_auth(3), rpc_clnt_calls(3), rpcbind(8)May 7, 1993 | Debian |