rpc_clnt_cr(3N)

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

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 data packet to the server.
     Upon receipt of the packet, the server calls a dispatch routine to
     perform the requested service, and then sends back a reply.

   Routines
     See rpc(3N) for the definition of the CLIENT data structure.

     #include <rpc/rpc.h>

     bool_t
     clnt_control(CLIENT *clnt, const u_int req, char *info);

          A function macro used 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 timevalset total timeout
          CLGET_TIMEOUT           struct timevalget total timeout

          Note: if you set the timeout using clnt_control, the timeout
          parameter passed to clnt_call will be ignored in all future calls.
          CLGET_FD    int         get the associated file descriptor
          CLGET_SVC_ADDR          struct netbufget servers address
          CLSET_FD_CLOSE          intclose the file descriptor when
                                  destroying the client handle
                                  [see clnt_destroy]
          CLSET_FD_NCLOSE         intdo not close the file
                                  descriptor when destroying
                                  the client handle

          The following operations are valid for connectionless transports
          only:
          CLSET_RETRY_TIMEOUT      struct timevalset the retry timeout
          CLGET_RETRY_TIMEOUT      struct timevalget the retry timeout

          The retry timeout is the time that RPC waits for the server to reply
          before retransmitting the request.
          clnt_control returns 1 on success and 0 on failure.

     CLIENT *
     clnt_create(const char *host, const u_long prognum,
          const u_long versnum, const char *nettype);

          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 variable or in top to down order in the netconfig database.

          clnt_create tries all the transports of the nettype class available
          from the NETPATH environment variable and the netconfig database,
          and chooses the first successful one.  Default timeouts are set, but
          can be modified using clnt_control.

     void
     clnt_destroy(CLIENT *clnt);

          A function macro that destroys the client's RPC handle.  Destruction
          usually involves deallocation of private data structures, including
          clnt itself.  Use of clnt is undefined after calling clnt_destroy.
          If the RPC library opened the associated file descriptor, or
          CLSET_FD_CLOSE was set using clnt_control, it will be closed.

     CLIENT *
     clnt_dg_create(const int fd, const struct netbuf *svcaddr,
          const u_long prognum, const u_long versnum,
          const u_int sendsz, const u_int recvsz);

          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 fd
          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(3N)].
          This routine returns NULL if it fails.  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.

     void
     clnt_pcreateerror(const char *s);

          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.

     CLIENT *
     clnt_raw_create(const u_long prognum, const u_long versnum);

          This routine creates a toy RPC client 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_clnt_calls(3N)].  This allows simulation of
          RPC and acquisition of RPC overheads, such as round trip times,
          without any kernel interference.  This routine returns NULL if it
          fails.  clnt_raw_create should be called after svc_raw_create.

     char *
     clnt_spcreateerror(const char *s);

          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.

          Note:  returns a pointer to static data that is overwritten on each
          call.

     CLIENT *
     clnt_tli_create(const int fd, const struct netconfig *netconf,
          const struct netbuf *svcaddr, u const_long prognum,
          const u_long versnum, const u_int sendsz,
          const u_int recvsz);

          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 is NULL, RPC_UNKNOWNADDR error
          is set.  fd 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 netconf is NULL, a
          RPC_UNKNOWNPROTO error is set.  If fd is unbound, then it will
          attempt to bind the descriptor.  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_pcreaterror routine can be used to print the
          reason for failure.  The remote rpcbind service [see rpcbind(1M)]
          will not be consulted for the address of the remote service.

     CLIENT *
     clnt_tp_create(const char *host, const u_long prognum,
          const u_long versnum, const struct netconfig *netconf);

          clnt_tp_create creates a client handle 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_pcreaterror routine can be used
          to print the reason for failure.

     CLIENT *
     clnt_vc_create(const int fd, const struct netbuf *svcaddr,
          const u_long prognum, const u_long versnum,
          const u_int sendsz, const u_int recvsz);

          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
          parameter fd 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 will not
          consult the remote rpcbind service for this information.

SEE ALSO
     rpcbind(1M), rpc(3N), rpc_clnt_auth(3N), rpc_clnt_calls(3N)