table of contents
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 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 byclnt_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 returnsTRUE
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. Theclnt_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 usingclnt_control
(). This routine returnsNULL
if it fails. Theclnt_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 toclnt_create
() is not registered with the rpcbind(8) service. This mismatch will be discovered by aclnt_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, theclnt_create_timed
() call behaves exactly like theclnt_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 returnsNULL
. A default timeout is set and can be modified usingclnt_control
(). This routine returnsNULL
if it fails. Theclnt_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 toclnt_create
() is not registered with the rpcbind(8) service. This mismatch will be discovered by aclnt_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, theclnt_create_vers_timed
() call behaves exactly like theclnt_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, orCLSET_FD_CLOSE
was set usingclnt_control
(), the file descriptor will be closed. The caller should callauth_destroy
(clnt->cl_auth) (before callingclnt_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
() (seeclnt_call
() in rpc_clnt_calls(3)). The retry time out and the total time out periods can be changed usingclnt_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 returnsNULL
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 returnsNULL
if it fails. Theclnt_raw_create
() function should be called aftersvc_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. Theclnt_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
() exceptclnt_tp_create
() tries only one transport specified through netconf. Theclnt_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 usingclnt_control
() calls. The remote rpcbind service on the host host is consulted for the address of the remote service. This routine returnsNULL
if it fails. Theclnt_pcreateerror
() routine can be used to print the reason for failure. clnt_tp_create_timed
()- Like
clnt_tp_create
() exceptclnt_tp_create_timed
() has the extra argument timeout which specifies the maximum time allowed for the creation attempt to succeed. In all other respects, theclnt_tp_create_timed
() call behaves exactly like theclnt_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. Theclnt_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¶
May 7, 1993 | Linux 5.14.0-427.18.1.el9_4.x86_64 |