RPC_CLNT_CREATE(3)



RPC_CLNT_CREATE(3)       BSD Library Functions Manual       RPC_CLNT_CREATE(3)

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

SYNOPSIS
     #include <rpc/rpc.h>

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

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

     CLIENT *
     clnt_create_timed(const char * host, const rpcprog_t prognum,
         const rpcvers_t versnum, const char *nettype,
         const struct timeval *timeout);

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

     CLIENT *
     clnt_create_vers_timed(const char * host, const rpcprog_t prognum,
         rpcvers_t *vers_outp, const rpcvers_t vers_low,
         const rpcvers_t vers_high, char *nettype,
         const struct timeval *timeout);

     void
     clnt_destroy(CLIENT *clnt);

     CLIENT *
     clnt_dg_create(const int fildes, const struct netbuf *svcaddr,
         const rpcprog_t prognum, const rpcvers_t versnum, const u_int sendsz,
         const u_int recvsz);

     void
     clnt_pcreateerror(const char *s);

     char *
     clnt_spcreateerror(const char *s);

     CLIENT *
     clnt_raw_create(const rpcprog_t prognum, const rpcvers_t versnum);

     CLIENT *
     clnt_tli_create(const int fildes, const struct netconfig *netconf,
         const struct netbuf *svcaddr, const rpcprog_t prognum,
         const rpcvers_t versnum, const u_int sendsz, const u_int recvsz);

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

     CLIENT *
     clnt_tp_create_timed(const char * host, const rpcprog_t prognum,
         const rpcvers_t versnum, const struct netconfig *netconf,
         const struct timeval *timeout);

     CLIENT *
     clnt_vc_create(const int fildes, const struct netbuf *svcaddr,
         const rpcprog_t prognum, const rpcvers_t versnum, u_int sendsz,
         u_int recvsz);

DESCRIPTION
     RPC library routines allow C language programs to make procedure calls on
     other machines across the network.  First a CLIENT handle is created and
     then the client calls a procedure to send a request to the server.  On
     receipt of the request, the server calls a dispatch routine to perform
     the requested service, and then sends a reply.

Routines
     clnt_control()
              A function macro to change or retrieve various information about
              a client object.  The req argument indicates the type of opera-
              tion, and info is a pointer to the information.  For both con-
              nectionless 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 argument
              to 0 for batching calls.

              CLGET_SVC_ADDR     struct netbuf *     get servers address
              CLGET_FD           int *               get fd from handle
              CLSET_FD_CLOSE     void                close fd on destroy
              CLSET_FD_NCLOSE    void                don't close fd on destroy
              CLGET_VERS         u_int32_t *         get RPC program version
              CLSET_VERS         u_int32_t *         set RPC program version
              CLGET_XID          u_int32_t *         get XID of previous call
              CLSET_XID          u_int32_t *         set XID of next call

              The following operations are valid for connectionless transports
              only:

              CLSET_RETRY_TIMEOUT    struct timeval *    set the retry timeout
              CLGET_RETRY_TIMEOUT    struct timeval *    get the retry timeout
              CLSET_CONNECT          int *               use connect(2)

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

     clnt_create()
              Generic client creation routine for program prognum and version
              versnum.  The host argument identifies the name of the remote
              host where the server is located.  The nettype argument indi-
              cates 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.  The
              clnt_create() function tries all the transports of the nettype
              class available from the NETPATH environment variable and the
              netconfig database, and chooses the first successful one.  A de-
              fault 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_timed()
              Generic client creation routine which is similar to
              clnt_create() but which also has the additional argument timeout
              that specifies the maximum amount of time allowed for each
              transport class tried.  In all other respects, the
              clnt_create_timed() call behaves exactly like the clnt_create()
              call.

     clnt_create_vers()
              Generic client creation routine which is similar to
              clnt_create() but which also checks for the version availabil-
              ity.  The host argument identifies the name of the remote host
              where the server is located.  The nettype argument indicates the
              class transport protocols to be used.  If the routine is suc-
              cessful it returns a client handle created for the highest ver-
              sion between vers_low and vers_high that is supported by the
              server.  The vers_outp argument is set to this value.  That is,
              after a successful return vers_low <= *vers_outp <= vers_high.
              If no version between vers_low and vers_high is supported by the
              server then the routine fails and returns NULL.  A default time-
              out is set and can be modified using clnt_control().  This rou-
              tine 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 particu-
              lar 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_create_vers_timed()
              Generic client creation routine which is similar to
              clnt_create_vers() but which also has the additional argument
              timeout that specifies the maximum amount of time allowed for
              each transport class tried.  In all other respects, the
              clnt_create_vers_timed() call behaves exactly like the
              clnt_create_vers() call.

     clnt_destroy()
              A function macro that destroys the client's RPC handle.  De-
              struction 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 fildes argument is an open and bound file descriptor.  This
              routine will resend the call message in intervals of 15 seconds
              until a response is received or until the call times out.  The
              total time for the call to time out is specified by clnt_call()
              (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 sendsz and recvsz arguments; values of 0 choose suitable de-
              faults.  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 in-
              stead of printing to the standard error.  A newline is not ap-
              pended 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 in-
              terference.  This routine returns NULL if it fails.  The
              clnt_raw_create() function 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.  The fildes argument 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 er-
              ror is set.  If fildes is unbound, then it will attempt to bind
              the descriptor.  The user may specify the size of the buffers
              with the sendsz and recvsz arguments; values of 0 choose suit-
              able defaults.  Depending upon the type of the transport (con-
              nection-oriented or connectionless), clnt_tli_create() calls ap-
              propriate 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 ser-
              vice.

     clnt_tp_create()
              Like clnt_create() except clnt_tp_create() tries only one trans-
              port specified through netconf.  The clnt_tp_create() function
              creates a client handle for the program prognum, the version
              versnum, and for the transport specified by netconf.  Default
              options are set, which can be changed 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_tp_create_timed()
              Like clnt_tp_create() except clnt_tp_create_timed() has the ex-
              tra argument timeout which specifies the maximum time allowed
              for the creation attempt to succeed.  In all other respects, the
              clnt_tp_create_timed() call behaves exactly like the
              clnt_tp_create() call.

     clnt_vc_create()
              This routine creates an RPC client for the remote program
              prognum and version versnum; the client uses a connection-ori-
              ented transport.  The remote program is located at address
              svcaddr.  The fildes argument is an open and bound file descrip-
              tor.  The user may specify the size of the send and receive buf-
              fers with the sendsz and recvsz arguments; 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 ac-
              tual address of the remote program.  The clnt_vc_create() func-
              tion does not consult the remote rpcbind service for this infor-
              mation.

     struct rpc_createerr rpc_createerr;
              A global variable whose value is set by any RPC client handle
              creation routine that fails.  It is used by the routine
              clnt_pcreateerror() to print the reason for the failure.

AVAILABILITY
     These functions are part of libtirpc.

SEE ALSO
     rpc(3), rpc_clnt_auth(3), rpc_clnt_calls(3), rpcbind(8)

BSD                               May 7, 1993                              BSD

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