RPC_CLNT_CREATE(3)      NetBSD Library Functions Manual     RPC_CLNT_CREATE(3)

NAME
     rpc_clnt_create, clnt_control, clnt_create, clnt_create_vers,
     clnt_destroy, clnt_dg_create, clnt_pcreateerror, clnt_raw_create,
     clnt_spcreateerror, clnt_tli_create, clnt_tp_create, clnt_vc_create,
     rpc_createerr -- library routines for dealing with creation and manipula-
     tion of CLIENT handles

LIBRARY
     Standard C Library (libc, -lc)

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_vers(const char * host, const rpcprog_t prognum,
         rpcvers_t *vers_outp, const rpcvers_t vers_low,
         const rpcvers_t vers_high, char *nettype);

     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_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);

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.  req indicates the type of operation, and info
              is a pointer to the information.  For both connectionless and
              connection-oriented transports, the supported values of req and
              their argument types and what they do are:

              CLSET_TIMEOUT      struct timeval *    set total timeout
              CLGET_TIMEOUT      struct timeval *    get total timeout

              Note: if you set the timeout using clnt_control(), the timeout
              argument passed by clnt_call() is ignored in all subsequent
              calls.

              Note: If you set the timeout value to 0 clnt_control() immedi-
              ately returns an error ( RPC_TIMEDOUT).  Set the timeout parame-
              ter 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         unsigned long *     get RPC program version
              CLSET_VERS         unsigned long *     set RPC program version
              CLGET_XID          unsigned long *     get XID of previous call
              CLSET_XID          unsigned long *     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

              The retry timeout is the time that RPC waits for the server to
              reply before retransmitting the request.  clnt_control() returns
              TRUE on success and FALSE on failure.

     clnt_create()
              Generic client creation routine for program prognum and version
              versnum.  host identifies the name of the remote host where the
              server is located.  nettype 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.  clnt_create() tries all the trans-
              ports of the nettype class available from the NETPATH environ-
              ment variable and the netconfig database, and chooses the first
              successful one.  A default timeout is set and can be modified
              using clnt_control().  This routine returns NULL if it fails.
              The clnt_pcreateerror() routine can be used to print the reason
              for failure.

              Note: clnt_create() returns a valid client handle even if the
              particular version number supplied to clnt_create() is not reg-
              istered with the rpcbind(8) service.  This mismatch will be dis-
              covered by a clnt_call() later (see rpc_clnt_calls(3)).

     clnt_create_vers()
              Generic client creation routine which is similar to
              clnt_create() but which also checks for the version availabil-
              ity.  host identifies the name of the remote host where the
              server is located.  nettype indicates the class transport proto-
              cols 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.  vers_outp is set
              to this value.  That is, after a successful return vers_low <=
              *vers_outp <= vers_high.  If no version between vers_low and
              vers_high is supported by the server then the routine fails and
              returns NULL.  A default timeout is set and can be modified
              using clnt_control().  This routine returns NULL if it fails.
              The clnt_pcreateerror() routine can be used to print the reason
              for failure.  Note: clnt_create() returns a valid client handle
              even if the particular version number supplied to clnt_create()
              is not registered with the rpcbind(8) service.  This mismatch
              will be discovered by a clnt_call() later (see
              rpc_clnt_calls(3)).  However, clnt_create_vers() does this for
              you and returns a valid handle only if a version within the
              range supplied is supported by the server.

     clnt_destroy()
              A function macro that destroys the client's RPC handle.
              Destruction usually involves deallocation of private data struc-
              tures, including clnt itself.  Use of clnt is undefined after
              calling clnt_destroy().  If the RPC library opened the associ-
              ated 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 parameter fildes 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 parameters sendsz and recvsz; 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 mes-
              sages 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.
              clnt_raw_create() 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-ori-
              ented, it is assumed that the file descriptor is connected.  For
              connectionless transports, if svcaddr is NULL, RPC_UNKNOWNADDR
              error is set.  fildes is a file descriptor which may be open,
              bound and connected.  If it is RPC_ANYFD, it opens a file
              descriptor on the transport specified by netconf.  If fildes is
              RPC_ANYFD and netconf is NULL, a RPC_UNKNOWNPROTO error is set.
              If fildes is unbound, then it will attempt to bind the descrip-
              tor.  The user may specify the size of the buffers with the
              parameters sendsz and recvsz; values of 0 choose suitable
              defaults.  Depending upon the type of the transport (connection-
              oriented or connectionless), clnt_tli_create() calls appropriate
              client creation routines.  This routine returns NULL if it
              fails.  The clnt_pcreateerror() routine can be used to print the
              reason for failure.  The remote rpcbind service (see rpcbind(8))
              is not consulted for the address of the remote service.

     clnt_tp_create()
              Like clnt_create() except clnt_tp_create() tries only one trans-
              port specified through netconf.  clnt_tp_create() 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_vc_create()
              This routine creates an RPC client for the remote program
              prognum and version versnum; the client uses a connection-ori-
              ented transport.  The remote program is located at address
              svcaddr.  The parameter fildes is an open and bound file
              descriptor.  The user may specify the size of the send and
              receive buffers with the parameters sendsz and recvsz; values of
              0 choose suitable defaults.  This routine returns NULL if it
              fails.  The address svcaddr should not be NULL and should point
              to the actual address of the remote program.  clnt_vc_create()
              does not consult the remote rpcbind service for this informa-
              tion.

     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)

NetBSD 5.0_STABLE                 May 7, 1993                NetBSD 5.0_STABLE
