32de72d27f
whether or not connect(2) is used for UDP client sockets. The default is not to connect(), so existing clients will see no change in behaviour. The use of connect(2) for UDP clients has a number of advantages: only replies from the intended address are received, and ICMP errors pertaining to the connection are reported back to the application.
439 lines
12 KiB
Groff
439 lines
12 KiB
Groff
.\" @(#)rpc_clnt_create.3n 1.36 93/08/31 SMI; from SVr4
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.\" Copyright 1989 AT&T
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.\" @(#)rpc_clnt_create 1.5 89/07/24 SMI;
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.\" Copyright (c) 1988 Sun Microsystems, Inc. - All Rights Reserved.
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.\" $NetBSD: rpc_clnt_create.3,v 1.2 2000/06/20 00:53:08 fvdl Exp $
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.\" $FreeBSD$
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.Dd May 7, 1993
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.Dt RPC_CLNT_CREATE 3
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.Os
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.Sh NAME
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.Nm rpc_clnt_create ,
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.Nm clnt_control ,
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.Nm clnt_create ,
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.Nm clnt_create_vers ,
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.Nm clnt_destroy ,
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.Nm clnt_dg_create ,
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.Nm clnt_pcreateerror ,
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.Nm clnt_raw_create ,
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.Nm clnt_spcreateerror ,
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.Nm clnt_tli_create ,
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.Nm clnt_tp_create ,
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.Nm clnt_vc_create ,
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.Nm rpc_createerr
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.Nd "library routines for dealing with creation and manipulation of"
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.Vt CLIENT
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handles
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.Sh LIBRARY
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.Lb libc
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.Sh SYNOPSIS
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.Fd #include <rpc/rpc.h>
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.Ft bool_t
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.Fn clnt_control "CLIENT *clnt" "const u_int req" "char *info"
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.Ft "CLIENT *"
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.Fn clnt_create "const char * host" "const rpcprog_t prognum" "const rpcvers_t versnum" "const char *nettype"
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.Ft "CLIENT *"
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.Fn clnt_create_vers "const char * host" "const rpcprog_t prognum" "rpcvers_t *vers_outp" "const rpcvers_t vers_low" "const rpcvers_t vers_high" "char *nettype"
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.Ft void
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.Fn clnt_destroy "CLIENT *clnt"
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.Ft "CLIENT *"
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.Fn 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"
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.Ft void
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.Fn clnt_pcreateerror "const char *s"
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.Ft "char *"
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.Fn clnt_spcreateerror "const char *s"
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.Ft "CLIENT *"
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.Fn clnt_raw_create "const rpcprog_t prognum" "const rpcvers_t versnum"
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.Ft "CLIENT *"
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.Fn 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"
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.Ft "CLIENT *"
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.Fn clnt_tp_create "const char * host" "const rpcprog_t prognum" "const rpcvers_t versnum" "const struct netconfig *netconf"
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.Ft "CLIENT *"
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.Fn clnt_vc_create "const int fildes" "const struct netbuf *svcaddr" "const rpcprog_t prognum" "const rpcvers_t versnum" "const u_int sendsz" "const u_int recvsz"
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.Sh DESCRIPTION
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RPC library routines allow C language programs to make procedure
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calls on other machines across the network.
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First a
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.Vt CLIENT
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handle is created and then the client calls a procedure to send a
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request to the server.
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On receipt of the request, the server calls a dispatch routine
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to perform the requested service, and then sends a reply.
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.Sh Routines
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.Bl -tag -width YYYYYYY
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.It Fn clnt_control
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A function macro to change or retrieve various information
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about a client object.
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.Fa req
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indicates the type of operation, and
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.Fa info
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is a pointer to the information.
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For both connectionless and connection-oriented transports,
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the supported values of
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.Fa req
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and their argument types and what they do are:
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.Bl -column "CLSET_FD_NCLOSE" "struct timeval *" "set total timeout"
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.It Dv CLSET_TIMEOUT Ta "struct timeval *" Ta "set total timeout"
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.It Dv CLGET_TIMEOUT Ta "struct timeval *" Ta "get total timeout"
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.El
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.Pp
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Note:
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if you set the timeout using
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.Fn clnt_control ,
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the timeout argument passed by
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.Fn clnt_call
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is ignored in all subsequent calls.
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.Pp
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Note:
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If you set the timeout value to 0,
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.Fn clnt_control
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immediately returns an error
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.Pq Dv RPC_TIMEDOUT .
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Set the timeout parameter to 0 for batching calls.
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.Bl -column CLSET_FD_NCLOSE "struct timeval *" "do not close fd on destroy"
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.It Dv CLGET_SVC_ADDR Ta "struct netbuf *" Ta "get servers address"
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.It Dv CLGET_FD Ta "int *" Ta "get fd from handle"
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.It Dv CLSET_FD_CLOSE Ta "void" Ta "close fd on destroy"
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.It Dv CLSET_FD_NCLOSE Ta void Ta "don't close fd on destroy"
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.It Dv CLGET_VERS Ta "unsigned long *" Ta "get RPC program version"
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.It Dv CLSET_VERS Ta "unsigned long *" Ta "set RPC program version"
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.It Dv CLGET_XID Ta "unsigned long *" Ta "get XID of previous call"
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.It Dv CLSET_XID Ta "unsigned long *" Ta "set XID of next call"
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.El
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.Pp
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The following operations are valid for connectionless transports only:
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.Bl -column CLSET_RETRY_TIMEOUT "struct timeval *" "set total timeout"
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.It Dv CLSET_RETRY_TIMEOUT Ta "struct timeval *" Ta "set the retry timeout"
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.It Dv CLGET_RETRY_TIMEOUT Ta "struct timeval *" Ta "get the retry timeout"
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.It Dv CLSET_CONNECT Ta Vt "int *" Ta use Xr connect 2
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.El
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.Pp
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The retry timeout is the time that RPC
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waits for the server to reply before retransmitting the request.
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.Fn clnt_control
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returns
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.Dv TRUE
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on success and
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.Dv FALSE
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on failure.
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.It Fn clnt_create
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Generic client creation routine for program
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.Fa prognum
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and version
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.Fa versnum .
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.Fa host
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identifies the name of the remote host where the server
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is located.
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.Fa nettype
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indicates the class of transport protocol to use.
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The transports are tried in left to right order in
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.Ev NETPATH
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environment variable or in top to bottom order in
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the netconfig database.
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.Fn clnt_create
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tries all the transports of the
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.Fa nettype
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class available from the
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.Ev NETPATH
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environment variable and the netconfig database,
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and chooses the first successful one.
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A default timeout is set and can be modified using
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.Fn clnt_control .
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This routine returns
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.Dv NULL
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if it fails.
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The
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.Fn clnt_pcreateerror
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routine can be used to print the reason for failure.
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.Pp
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Note:
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.Fn clnt_create
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returns a valid client handle even
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if the particular version number supplied to
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.Fn clnt_create
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is not registered with the
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.Xr rpcbind 8
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service.
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This mismatch will be discovered by a
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.Fn clnt_call
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later (see
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.Xr rpc_clnt_calls 3 ) .
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.It Fn clnt_create_vers
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Generic client creation routine which is similar to
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.Fn clnt_create
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but which also checks for the
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version availability.
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.Fa host
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identifies the name of the remote host where the server
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is located.
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.Fa nettype
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indicates the class transport protocols to be used.
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If the routine is successful it returns a client handle created for
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the highest version between
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.Fa vers_low
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and
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.Fa vers_high
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that is supported by the server.
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.Fa vers_outp
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is set to this value.
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That is, after a successful return
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.Fa vers_low
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<=
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.Fa *vers_outp
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<=
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.Fa vers_high .
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If no version between
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.Fa vers_low
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and
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.Fa vers_high
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is supported by the server then the routine fails and returns
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.Dv NULL .
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A default timeout is set and can be modified using
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.Fn clnt_control .
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This routine returns
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.Dv NULL
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if it fails.
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The
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.Fn clnt_pcreateerror
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routine can be used to print the reason for failure.
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Note:
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.Fn clnt_create
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returns a valid client handle even
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if the particular version number supplied to
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.Fn clnt_create
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is not registered with the
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.Xr rpcbind 8
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service.
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This mismatch will be discovered by a
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.Fn clnt_call
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later (see
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.Xr rpc_clnt_calls 3 ) .
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However,
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.Fn clnt_create_vers
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does this for you and returns a valid handle
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only if a version within
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the range supplied is supported by the server.
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.It Fn clnt_destroy
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A function macro that destroys the client's RPC handle.
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Destruction usually involves deallocation
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of private data structures, including
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.Fa clnt
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itself.
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Use of
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.Fa clnt
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is undefined after calling
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.Fn clnt_destroy .
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If the RPC library opened the associated file descriptor, or
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.Dv CLSET_FD_CLOSE
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was set using
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.Fn clnt_control ,
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the file descriptor will be closed.
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The caller should call
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.Fn auth_destroy "clnt->cl_auth"
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(before calling
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.Fn clnt_destroy )
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to destroy the associated
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.Vt AUTH
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structure (see
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.Xr rpc_clnt_auth 3 ) .
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.It Fn clnt_dg_create
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This routine creates an RPC client for the remote program
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.Fa prognum
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and version
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.Fa versnum ;
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the client uses a connectionless transport.
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The remote program is located at address
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.Fa svcaddr .
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The parameter
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.Fa fildes
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is an open and bound file descriptor.
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This routine will resend the call message in intervals of
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15 seconds until a response is received or until the
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call times out.
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The total time for the call to time out is specified by
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.Fn clnt_call
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(see
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.Fn clnt_call
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in
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.Xr rpc_clnt_calls 3 ) .
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The retry time out and the total time out periods can
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be changed using
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.Fn clnt_control .
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The user may set the size of the send and receive
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buffers with the parameters
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.Fa sendsz
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and
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.Fa recvsz ;
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values of 0 choose suitable defaults.
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This routine returns
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.Dv NULL
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if it fails.
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.It Fn clnt_pcreateerror
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Print a message to standard error indicating
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why a client RPC handle could not be created.
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The message is prepended with the string
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.Fa s
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and a colon, and appended with a newline.
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.It Fn clnt_spcreateerror
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Like
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.Fn clnt_pcreateerror ,
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except that it returns a string
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instead of printing to the standard error.
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A newline is not appended to the message in this case.
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Warning:
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returns a pointer to a buffer that is overwritten
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on each call.
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.It Fn clnt_raw_create
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This routine creates an RPC
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client handle for the remote program
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.Fa prognum
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and version
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.Fa versnum .
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The transport used to pass messages to the service is
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a buffer within the process's address space,
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so the corresponding RPC
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server should live in the same address space;
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(see
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.Fn svc_raw_create
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in
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.Xr rpc_svc_create 3 ) .
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This allows simulation of RPC and measurement of
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RPC overheads, such as round trip times,
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without any kernel or networking interference.
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This routine returns
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.Dv NULL
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if it fails.
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.Fn clnt_raw_create
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should be called after
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.Fn svc_raw_create .
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.It Fn clnt_tli_create
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This routine creates an RPC
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client handle for the remote program
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.Fa prognum
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and version
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.Fa versnum .
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The remote program is located at address
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.Fa svcaddr .
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If
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.Fa svcaddr
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is
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.Dv NULL
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and it is connection-oriented, it is assumed that the file descriptor
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is connected.
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For connectionless transports, if
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.Fa svcaddr
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is
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.Dv NULL ,
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.Dv RPC_UNKNOWNADDR
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error is set.
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.Fa fildes
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is a file descriptor which may be open, bound and connected.
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If it is
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.Dv RPC_ANYFD ,
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it opens a file descriptor on the transport specified by
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.Fa netconf .
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If
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.Fa fildes
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is
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.Dv RPC_ANYFD
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and
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.Fa netconf
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is
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.Dv NULL ,
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a
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.Dv RPC_UNKNOWNPROTO
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error is set.
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If
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.Fa fildes
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is unbound, then it will attempt to bind the descriptor.
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The user may specify the size of the buffers with the parameters
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.Fa sendsz
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and
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.Fa recvsz ;
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values of 0 choose suitable defaults.
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Depending upon the type of the transport (connection-oriented
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or connectionless),
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.Fn clnt_tli_create
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calls appropriate client creation routines.
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This routine returns
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.Dv NULL
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if it fails.
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The
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.Fn clnt_pcreateerror
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routine can be used to print the reason for failure.
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The remote rpcbind
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service (see
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.Xr rpcbind 8 )
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is not consulted for the address of the remote
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service.
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.It Fn clnt_tp_create
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Like
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.Fn clnt_create
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except
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.Fn clnt_tp_create
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tries only one transport specified through
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.Fa netconf .
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.Fn clnt_tp_create
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creates a client handle for the program
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.Fa prognum ,
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the version
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.Fa versnum ,
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and for the transport specified by
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.Fa netconf .
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Default options are set,
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which can be changed using
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.Fn clnt_control
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calls.
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The remote rpcbind service on the host
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.Fa host
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is consulted for the address of the remote service.
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This routine returns
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.Dv NULL
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if it fails.
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The
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.Fn clnt_pcreateerror
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routine can be used to print the reason for failure.
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.It Fn clnt_vc_create
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This routine creates an RPC
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client for the remote program
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.Fa prognum
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and version
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.Fa versnum ;
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the client uses a connection-oriented transport.
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The remote program is located at address
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.Fa svcaddr .
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The parameter
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.Fa fildes
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is an open and bound file descriptor.
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The user may specify the size of the send and receive buffers
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with the parameters
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.Fa sendsz
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and
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.Fa recvsz ;
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values of 0 choose suitable defaults.
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This routine returns
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.Dv NULL
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if it fails.
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The address
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.Fa svcaddr
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should not be
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.Dv NULL
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and should point to the actual address of the remote program.
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.Fn clnt_vc_create
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does not consult the remote rpcbind service for this information.
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.It Xo
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.Vt "struct rpc_createerr" Va rpc_createerr ;
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.Xc
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A global variable whose value is set by any RPC
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client handle creation routine
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that fails.
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It is used by the routine
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.Fn clnt_pcreateerror
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to print the reason for the failure.
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.El
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.Sh SEE ALSO
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.Xr rpc 3 ,
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.Xr rpc_clnt_auth 3 ,
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.Xr rpc_clnt_calls 3 ,
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.Xr rpcbind 8
|