rpc — library routines for remote procedure calls
These routines allow C programs to make procedure calls on other machines across the network. First, 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. Finally, the procedure call returns to the client.
To take use of these routines, include the header file
      <rpc/rpc.h>
The prototypes below make use of the following types:
typedef int bool_t; typedef bool_t (*xdrproc_t) (XDR *, void *,...); typedef bool_t (*resultproc_t) (caddr_t resp, struct sockaddr_in *raddr);
See the header files for the declarations of the
      AUTH, CLIENT, SVCXPRT, and XDR types.
void auth_destroy( | 
                  AUTH * | auth); | 
                
A macro that destroys the authentication
              information associated with auth. Destruction
              usually involves deallocation of private data
              structures. The use of auth is undefined after
              calling auth_destroy().
AUTH *authnone_create( | 
                  
                  void); | 
                  
Create and return an RPC authentication handle that passes non-usable authentication information with each remote procedure call. This is the default authentication used by RPC.
AUTH *authunix_create( | 
                  char * | host, | 
| int | uid, | |
| int | gid, | |
| int | len, | |
| int * | aup_gids); | 
                
Create and return an RPC authentication handle
              that contains authentication information. The
              parameter host is the name of the
              machine on which the information was created;
              uid is the
              user's user ID; gid is the user's
              current group ID; len and aup_gids refer to a
              counted array of groups to which the user belongs. It
              is easy to impersonate a user.
AUTH *authunix_create_default( | 
                  
                  void); | 
                  
Calls authunix_create() with the
              appropriate parameters.
int callrpc( | 
                  char * | host, | 
| unsigned long | prognum, | |
| unsigned long | versnum, | |
| unsigned long | procnum, | |
| char * | in, | |
| char * | out, | |
| xdrproc_t | inproc, | |
| xdrproc_t | outproc); | 
                
Call the remote procedure associated with
              prognum,
              versnum, and
              procnum on
              the machine, host. The parameter
              in is the
              address of the procedure's argument(s), and
              out is the
              address of where to place the result(s); inproc is used to
              encode the procedure's parameters, and outproc is used to
              decode the procedure's results. This routine returns
              zero if it succeeds, or the value of enum clnt_stat cast to an
              integer if it fails. The routine clnt_perrno() is handy for
              translating failure statuses into messages.
![]()  | 
                    Warning | 
|---|---|
| 
                       Calling remote procedures with this
                      routine uses UDP/IP as a transport; see
                        | 
                  
enum clnt_stat clnt_broadcast( | 
                  unsigned long | prognum, | 
| unsigned long | versnum, | |
| unsigned long | procnum, | |
| char * | in, | |
| char * | out, | |
| xdrproc_t | inproc, | |
| xdrproc_t | outproc, | |
| resultproc_t | eachresult); | 
                
Like callrpc(),
              except the call message is broadcast to all locally
              connected broadcast nets. Each time it receives a
              response, this routine calls eachresult(), whose form is:
bool_t eachresult( | 
                  char * | out, | 
| struct sockaddr_in * | addr); | 
                
where out
              is the same as out passed to
              clnt_broadcast(),
              except that the remote procedure's output is decoded
              there; addr
              points to the address of the machine that sent the
              results. If eachresult() returns zero,
              clnt_broadcast() waits
              for more replies; otherwise it returns with
              appropriate status.
![]()  | 
                    Warning | 
|---|---|
| 
                       Broadcast sockets are limited in size to the maximum transfer unit of the data link. For ethernet, this value is 1500 bytes.  | 
                  
enum clnt_stat clnt_call( | 
                  CLIENT * | clnt, | 
| unsigned long | procnum, | |
| xdrproc_t | inproc, | |
| xdrproc_t | outproc, | |
| char * | in, | |
| char * | out, | |
| struct timeval | tout); | 
                
A macro that calls the remote procedure procnum associated with
              the client handle, clnt, which is obtained
              with an RPC client creation routine such as
              clnt_create(). The
              parameter in
              is the address of the procedure's argument(s), and
              out is the
              address of where to place the result(s); inproc is used to
              encode the procedure's parameters, and outproc is used to
              decode the procedure's results; tout is the time
              allowed for results to come back.
void clnt_destroy( | 
                  CLIENT * | clnt); | 
                
A 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 socket, it will close it also.
              Otherwise, the socket remains open.
CLIENT *clnt_create( | 
                  char * | host, | 
| unsigned long | prog, | |
| unsigned long | vers, | |
| char * | proto); | 
                
Generic client creation routine. host identifies the
              name of the remote host where the server is located.
              proto
              indicates which kind of transport protocol to use.
              The currently supported values for this field are
              “udp” and
              “tcp”. Default
              timeouts are set, but can be modified using
              clnt_control().
![]()  | 
                    Warning | 
|---|---|
| 
                       Using UDP has its shortcomings. Since UDP-based RPC messages can only hold up to 8 Kbytes of encoded data, this transport cannot be used for procedures that take large arguments or return huge results.  | 
                  
bool_t clnt_control( | 
                  CLIENT * | cl, | 
| int | req, | |
| char * | info); | 
                
A 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 UDP and TCP, the supported
              values of req
              and their argument types and what they do are:
CLSET_TIMEOUTstruct timeval // set total timeoutCLGET_TIMEOUTstruct timeval // get total timeout
![]()  | 
                    Note | 
|---|---|
| 
                       If you set the timeout using   | 
                  
CLGET_SERVER_ADDRstruct sockaddr_in // get server's address
The following operations are valid for UDP only:
CLSET_RETRY_TIMEOUTstruct timeval // set the retry timeoutCLGET_RETRY_TIMEOUTstruct timeval // get the retry timeout
The retry timeout is the time that "UDP RPC" waits for the server to reply before retransmitting the request.
bool_t clnt_freeres( | 
                  CLIENT * | clnt, | 
| xdrproc_t | outproc, | |
| char * | out); | 
                
A macro that frees any data allocated by the
              RPC/XDR system when it decoded the results of an RPC
              call. The parameter out is the address of
              the results, and outproc is the XDR
              routine describing the results. This routine returns
              one if the results were successfully freed, and zero
              otherwise.
void clnt_geterr( | 
                  CLIENT * | clnt, | 
| struct rpc_err * | errp); | 
                
A macro that copies the error structure out of the
              client handle to the structure at address errp.
void clnt_pcreateerror( | 
                  char * | s); | 
                
Print a message to standard error indicating why a
              client RPC handle could not be created. The message
              is prepended with string s and a colon. Used
              when a clnt_create(),
              clntraw_create(),
              clnttcp_create(), or
              clntudp_create() call
              fails.
void clnt_perrno( | 
                  enum clnt_stat | stat); | 
                
Print a message to standard error corresponding to
              the condition indicated by stat. Used after
              callrpc().
void clnt_perror( | 
                  CLIENT * | clnt, | 
| char * | s); | 
                
Print a message to standard error indicating why
              an RPC call failed; clnt is the handle used
              to do the call. The message is prepended with string
              s and a
              colon. Used after clnt_call().
char *clnt_spcreateerror( | 
                  char * | s); | 
                
Like clnt_pcreateerror(), except that it
              returns a string instead of printing to the standard
              error.
Bugs: returns pointer to static data that is overwritten on each call.
char *clnt_sperrno( | 
                  enum clnt_stat | stat); | 
                
Take the same arguments as clnt_perrno(), but instead of
              sending a message to the standard error indicating
              why an RPC call failed, return a pointer to a string
              which contains the message. The string ends with a
              NEWLINE.
clnt_sperrno() is
              used instead of clnt_perrno() if the program does
              not have a standard error (as a program running as a
              server quite likely does not), or if the programmer
              does not want the message to be output with printf(3), or if a
              message format different than that supported by
              clnt_perrno() is to be
              used. Note: unlike clnt_sperror() and clnt_spcreaterror(), clnt_sperrno() returns pointer to
              static data, but the result will not get overwritten
              on each call.
char *clnt_sperror( | 
                  CLIENT * | rpch, | 
| char * | s); | 
                
Like clnt_perror(),
              except that (like clnt_sperrno()) it returns a string
              instead of printing to standard error.
Bugs: returns pointer to static data that is overwritten on each call.
CLIENT *clntraw_create( | 
                  unsigned long | prognum, | 
| unsigned long | versnum); | 
                
This routine creates a toy RPC client for the
              remote program prognum, version
              versnum. The
              transport used to pass messages to the service is
              actually a buffer within the process's address space,
              so the corresponding RPC server should live in the
              same address space; see svcraw_create(). 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.
CLIENT *clnttcp_create( | 
                  struct sockaddr_in * | addr, | 
| unsigned long | prognum, | |
| unsigned long | versnum, | |
| int * | sockp, | |
| unsigned int | sendsz, | |
| unsigned int | recvsz); | 
                
This routine creates an RPC client for the remote
              program prognum, version
              versnum; the
              client uses TCP/IP as a transport. The remote program
              is located at Internet address *addr. If addr−>sin_port
              is zero, then it is set to the actual port that the
              remote program is listening on (the remote
              portmap service is
              consulted for this information). The parameter
              sockp is a
              socket; if it is RPC_ANYSOCK, then this routine
              opens a new one and sets sockp. Since TCP-based
              RPC uses buffered I/O, the user may specify the size
              of the send and receive buffers with the parameters
              sendsz and
              recvsz;
              values of zero choose suitable defaults. This routine
              returns NULL if it fails.
CLIENT *clntudp_create( | 
                  struct sockaddr_in * | addr, | 
| unsigned long | prognum, | |
| unsigned long | versnum, | |
| struct timeval | wait, | |
| int * | sockp); | 
                
This routine creates an RPC client for the remote
              program prognum, version
              versnum; the
              client uses use UDP/IP as a transport. The remote
              program is located at Internet address addr. If addr−>sin_port
              is zero, then it is set to actual port that the
              remote program is listening on (the remote
              portmap service is
              consulted for this information). The parameter
              sockp is a
              socket; if it is RPC_ANYSOCK, then this routine
              opens a new one and sets sockp. The UDP
              transport resends the call message in intervals of
              wait time
              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().
![]()  | 
                    Warning | 
|---|---|
| 
                       Since UDP-based RPC messages can only hold up to 8 Kbytes of encoded data, this transport cannot be used for procedures that take large arguments or return huge results.  | 
                  
CLIENT *clntudp_bufcreate( | 
                  struct sockaddr_in * | addr, | 
| unsigned long | prognum, | |
| unsigned long | versnum, | |
| struct timeval | wait, | |
| int * | sockp, | |
| unsigned int | sendsize, | |
| unsigned int | recosize); | 
                
This routine creates an RPC client for the remote
              program prognum, on versnum; the client
              uses use UDP/IP as a transport. The remote program is
              located at Internet address addr. If addr−>sin_port
              is zero, then it is set to actual port that the
              remote program is listening on (the remote
              portmap service is
              consulted for this information). The parameter
              sockp is a
              socket; if it is RPC_ANYSOCK, then this routine
              opens a new one and sets sockp. The UDP
              transport resends the call message in intervals of
              wait time
              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().
This allows the user to specify the maximum packet size for sending and receiving UDP-based RPC messages.
void get_myaddress( | 
                  struct sockaddr_in * | addr); | 
                
Stuff the machine's IP address into *addr, without
              consulting the library routines that deal with
              /etc/hosts. The port
              number is always set to htons(PMAPPORT).
struct pmaplist *pmap_getmaps( | 
                  struct sockaddr_in * | addr); | 
                
A user interface to the portmap service, which returns a
              list of the current RPC program-to-port mappings on
              the host located at IP address *addr. This routine can
              return NULL. The command rpcinfo −p uses this
              routine.
unsigned short pmap_getport( | 
                  struct sockaddr_in * | addr, | 
| unsigned long | prognum, | |
| unsigned long | versnum, | |
| unsigned int | protocol); | 
                
A user interface to the portmap service, which returns
              the port number on which waits a service that
              supports program number prognum, version
              versnum, and
              speaks the transport protocol associated with
              protocol. The
              value of protocol is most likely
              IPPROTO_UDP or
              IPPROTO_TCP. A return
              value of zero means that the mapping does not exist
              or that the RPC system failed to contact the remote
              portmap service. In
              the latter case, the global variable rpc_createerr contains the RPC
              status.
enum clnt_stat pmap_rmtcall( | 
                  struct sockaddr_in * | addr, | 
| unsigned long | prognum, | |
| unsigned long | versnum, | |
| unsigned long | procnum, | |
| char * | in, | |
| char * | out, | |
| xdrproc_t | inproc, | |
| xdrproc_t | outproc, | |
| struct timeval | tout, | |
| unsigned long * | portp); | 
                
A user interface to the portmap service, which instructs
              portmap on the host
              at IP address *addr to make an RPC
              call on your behalf to a procedure on that host. The
              parameter *portp will be modified
              to the program's port number if the procedure
              succeeds. The definitions of other parameters are
              discussed in callrpc()
              and clnt_call(). This
              procedure should be used for a “ping” and nothing else. See also
              clnt_broadcast().
bool_t pmap_set( | 
                  unsigned long | prognum, | 
| unsigned long | versnum, | |
| unsigned int | protocol, | |
| unsigned short | port); | 
                
A user interface to the portmap service, which
              establishes a mapping between the triple [prognum,versnum,protocol] and
              port on the
              machine's portmap
              service. The value of protocol is most likely
              IPPROTO_UDP or
              IPPROTO_TCP. This
              routine returns one if it succeeds, zero otherwise.
              Automatically done by svc_register().
bool_t pmap_unset( | 
                  unsigned long | prognum, | 
| unsigned long | versnum); | 
                
A user interface to the portmap service, which destroys
              all mapping between the triple [prognum,versnum,*] and ports on the machine's
              portmap service. This
              routine returns one if it succeeds, zero
              otherwise.
int registerrpc( | 
                  unsigned long | prognum, | 
| unsigned long | versnum, | |
| unsigned long | procnum, | |
| char * | (*procname)(char
                  *), | 
                |
| xdrproc_t | inproc, | |
| xdrproc_t | outproc); | 
                
Register procedure procname with the RPC
              service package. If a request arrives for program
              prognum,
              version versnum, and procedure
              procnum,
              procname is
              called with a pointer to its parameter(s);
              progname should
              return a pointer to its static result(s); inproc is used to
              decode the parameters while outproc is used to
              encode the results. This routine returns zero if the
              registration succeeded, −1 otherwise.
![]()  | 
                    Warning | 
|---|---|
| 
                       Remote procedures registered in this form
                      are accessed using the UDP/IP transport; see
                        | 
                  
A global variable whose value is set by any RPC
              client creation routine that does not succeed. Use
              the routine clnt_pcreateerror() to print the
              reason why.
void svc_destroy( | 
                  SVCXPRT * | xprt); | 
                
A macro that destroys the RPC service transport
              handle, xprt.
              Destruction usually involves deallocation of private
              data structures, including xprt itself. Use of
              xprt is
              undefined after calling this routine.
A global variable reflecting the RPC service
              side's read file descriptor bit mask; it is suitable
              as a parameter to the select(2) system
              call. This is only of interest if a service
              implementor does not call svc_run(), but rather does his own
              asynchronous event processing. This variable is
              read-only (do not pass its address to select(2)!), yet it
              may change after calls to svc_getreqset() or any creation
              routines.
Similar to svc_fdset,
              but limited to 32 descriptors. This interface is
              obsoleted by svc_fdset.
bool_t svc_freeargs( | 
                  SVCXPRT * | xprt, | 
| xdrproc_t | inproc, | |
| char * | in); | 
                
A macro that frees any data allocated by the
              RPC/XDR system when it decoded the arguments to a
              service procedure using svc_getargs(). This routine returns
              1 if the results were successfully freed, and zero
              otherwise.
bool_t svc_getargs( | 
                  SVCXPRT * | xprt, | 
| xdrproc_t | inproc, | |
| char * | in); | 
                
A macro that decodes the arguments of an RPC
              request associated with the RPC service transport
              handle, xprt.
              The parameter in is the address where
              the arguments will be placed; inproc is the XDR
              routine used to decode the arguments. This routine
              returns one if decoding succeeds, and zero
              otherwise.
struct sockaddr_in *svc_getcaller( | 
                  SVCXPRT * | xprt); | 
                
The approved way of getting the network address of
              the caller of a procedure associated with the RPC
              service transport handle, xprt.
void svc_getreqset( | 
                  fd_set * | rdfds); | 
                
This routine is only of interest if a service
              implementor does not call svc_run(), but instead implements
              custom asynchronous event processing. It is called
              when the select(2) system
              call has determined that an RPC request has arrived
              on some RPC socket(s); rdfds is the resultant
              read file descriptor bit mask. The routine returns
              when all sockets associated with the value of
              rdfds have
              been serviced.
void svc_getreq( | 
                  int | rdfds); | 
                
Similar to svc_getreqset(), but limited to 32
              descriptors. This interface is obsoleted by
              svc_getreqset().
bool_t svc_register( | 
                  SVCXPRT * | xprt, | 
| unsigned long | prognum, | |
| unsigned long | versnum, | |
| void | (*dispatch)(svc_req
                  *, SVCXPRT *), | 
                |
| unsigned long | protocol); | 
                
Associates prognum and versnum with the
              service dispatch procedure, dispatch. If protocol is zero, the
              service is not registered with the portmap service. If protocol is nonzero,
              then a mapping of the triple [prognum,versnum,protocol] to xprt−>xp_port
              is established with the local portmap service (generally
              protocol is
              zero, IPPROTO_UDP or
              IPPROTO_TCP). The
              procedure dispatch has the
              following form:
dispatch(struct svc_req *request, SVCXPRT *xprt);
The svc_register()
              routine returns one if it succeeds, and zero
              otherwise.
void svc_run(void);
              This routine never returns. It waits for RPC
              requests to arrive, and calls the appropriate service
              procedure using svc_getreq() when one arrives. This
              procedure is usually waiting for a select(2) system
              call to return.
bool_t svc_sendreply( | 
                  SVCXPRT * | xprt, | 
| xdrproc_t | outproc, | |
| char * | out); | 
                
Called by an RPC service's dispatch routine to
              send the results of a remote procedure call. The
              parameter xprt is the request's
              associated transport handle; outproc is the XDR
              routine which is used to encode the results; and
              out is the
              address of the results. This routine returns one if
              it succeeds, zero otherwise.
void svc_unregister( | 
                  unsigned long | prognum, | 
| unsigned long | versnum); | 
                
Remove all mapping of the double [prognum,versnum] to dispatch
              routines, and of the triple [prognum,versnum,*] to port number.
void svcerr_auth( | 
                  SVCXPRT * | xprt, | 
| enum auth_stat | why); | 
                
Called by a service dispatch routine that refuses to perform a remote procedure call due to an authentication error.
void svcerr_decode( | 
                  SVCXPRT * | xprt); | 
                
Called by a service dispatch routine that cannot
              successfully decode its parameters. See also
              svc_getargs().
void svcerr_noproc( | 
                  SVCXPRT * | xprt); | 
                
Called by a service dispatch routine that does not implement the procedure number that the caller requests.
void svcerr_noprog( | 
                  SVCXPRT * | xprt); | 
                
Called when the desired program is not registered with the RPC package. Service implementors usually do not need this routine.
void svcerr_progvers( | 
                  SVCXPRT * | xprt); | 
                
Called when the desired version of a program is not registered with the RPC package. Service implementors usually do not need this routine.
void svcerr_systemerr( | 
                  SVCXPRT * | xprt); | 
                
Called by a service dispatch routine when it detects a system error not covered by any particular protocol. For example, if a service can no longer allocate storage, it may call this routine.
void svcerr_weakauth( | 
                  SVCXPRT * | xprt); | 
                
Called by a service dispatch routine that refuses
              to perform a remote procedure call due to
              insufficient authentication parameters. The routine
              calls svcerr_auth(xprt, AUTH_TOOWEAK).
SVCXPRT *svcfd_create( | 
                  int | fd, | 
| unsigned int | sendsize, | |
| unsigned int | recvsize); | 
                
Create a service on top of any open descriptor.
              Typically, this descriptor is a connected socket for
              a stream protocol such as TCP. sendsize and recvsize indicate sizes
              for the send and receive buffers. If they are zero, a
              reasonable default is chosen.
SVCXPRT *svcraw_create( | 
                  
                  void); | 
                  
This routine creates a toy RPC service transport,
              to which it returns a pointer. The transport is
              really a buffer within the process's address space,
              so the corresponding RPC client should live in the
              same address space; see clntraw_create(). This routine
              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.
SVCXPRT *svctcp_create( | 
                  int | sock, | 
| unsigned int | send_buf_size, | |
| unsigned int | recv_buf_size); | 
                
This routine creates a TCP/IP-based RPC service
              transport, to which it returns a pointer. The
              transport is associated with the socket sock, which may be
              RPC_ANYSOCK, in which
              case a new socket is created. If the socket is not
              bound to a local TCP port, then this routine binds it
              to an arbitrary port. Upon completion, xprt−>xp_sock
              is the transport's socket descriptor, and xprt−>xp_port
              is the transport's port number. This routine returns
              NULL if it fails. Since TCP-based RPC uses buffered
              I/O, users may specify the size of buffers; values of
              zero choose suitable defaults.
SVCXPRT *svcudp_bufcreate( | 
                  int | sock, | 
| unsigned int | sendsize, | |
| unsigned int | recosize); | 
                
This routine creates a UDP/IP-based RPC service
              transport, to which it returns a pointer. The
              transport is associated with the socket sock, which may be
              RPC_ANYSOCK, in which
              case a new socket is created. If the socket is not
              bound to a local UDP port, then this routine binds it
              to an arbitrary port. Upon completion, xprt−>xp_sock
              is the transport's socket descriptor, and xprt−>xp_port
              is the transport's port number. This routine returns
              NULL if it fails.
This allows the user to specify the maximum packet size for sending and receiving UDP-based RPC messages.
SVCXPRT *svcudp_create( | 
                  int | sock); | 
                
This call is equivalent to svcudp_bufcreate(sock,SZ,SZ)
              for some default size SZ.
bool_t xdr_accepted_reply( | 
                  XDR * | xdrs, | 
| struct accepted_reply * | ar); | 
                
Used for encoding RPC reply messages. This routine is useful for users who wish to generate RPC-style messages without using the RPC package.
bool_t xdr_authunix_parms( | 
                  XDR * | xdrs, | 
| struct authunix_parms * | aupp); | 
                
Used for describing UNIX credentials. This routine is useful for users who wish to generate these credentials without using the RPC authentication package.
void xdr_callhdr( | 
                  XDR * | xdrs, | 
| struct rpc_msg * | chdr); | 
                
Used for describing RPC call header messages. This routine is useful for users who wish to generate RPC-style messages without using the RPC package.
bool_t xdr_callmsg( | 
                  XDR * | xdrs, | 
| struct rpc_msg * | cmsg); | 
                
Used for describing RPC call messages. This routine is useful for users who wish to generate RPC-style messages without using the RPC package.
bool_t xdr_opaque_auth( | 
                  XDR * | xdrs, | 
| struct opaque_auth * | ap); | 
                
Used for describing RPC authentication information messages. This routine is useful for users who wish to generate RPC-style messages without using the RPC package.
bool_t xdr_pmap( | 
                  XDR * | xdrs, | 
| struct pmap * | regs); | 
                
Used for describing parameters to various
              portmap procedures,
              externally. This routine is useful for users who wish
              to generate these parameters without using the
              pmap interface.
bool_t xdr_pmaplist( | 
                  XDR * | xdrs, | 
| struct pmaplist ** | rp); | 
                
Used for describing a list of port mappings, externally. This routine is useful for users who wish to generate these parameters without using the pmap interface.
bool_t xdr_rejected_reply( | 
                  XDR * | xdrs, | 
| struct rejected_reply * | rr); | 
                
Used for describing RPC reply messages. This routine is useful for users who wish to generate RPC-style messages without using the RPC package.
bool_t xdr_replymsg( | 
                  XDR * | xdrs, | 
| struct rpc_msg * | rmsg); | 
                
Used for describing RPC reply messages. This routine is useful for users who wish to generate RPC style messages without using the RPC package.
void xprt_register( | 
                  SVCXPRT * | xprt); | 
                
After RPC service transport handles are created,
              they should register themselves with the RPC service
              package. This routine modifies the global variable
              svc_fds.
              Service implementors usually do not need this
              routine.
void xprt_unregister( | 
                  SVCXPRT * | xprt); | 
                
Before an RPC service transport handle is
              destroyed, it should unregister itself with the RPC
              service package. This routine modifies the global
              variable svc_fds.
              Service implementors usually do not need this
              routine.
The following manuals:
Remote Procedure Calls: Protocol Specification
Remote Procedure Call Programming Guide
rpcgen Programming Guide
RPC: Remote Procedure Call Protocol Specification, RFC 1050, Sun Microsystems, Inc., USC-ISI.
This page is part of release 2.79 of the Linux man-pages project. A
      description of the project, and information about reporting
      bugs, can be found at
      http://www.kernel.org/doc/man-pages/.
| 
                 This page was taken from the 4.4BSD-Lite CDROM (BSD license) (#)rpc.3n 2.4 88/08/08 4.0 RPCSRC; from 1.19 88/06/24 SMI 2007-12-30, mtk, Convert function prototypes to modern C syntax  |