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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.In 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" "const 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
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