RPCGEN(1) BSD General Commands Manual RPCGEN(1)
rpcgen -- Remote Procedure Call (RPC) protocol compiler
rpcgen [-A] [-a] [-b] [-C] [-D name [=value]] [-I] [-i size] [-K secs] [-L] [-M] [-N] [-T]
[-v] [-Y pathname] infile
rpcgen -c | -h | -l | -m | -t | -Sc | -Ss [-o outfile] [infile]
rpcgen [-s nettype] [-o outfile] [infile]
rpcgen [-n netid] [-o outfile] [infile]
rpcgen is a tool that generates C code to implement an RPC protocol. The input to rpcgen is
a language similar to C known as RPC Language (Remote Procedure Call Language). rpcgen is
normally used as in the first synopsis where it takes an input file and generates up to four
output files. If the infile is named proto.x, then rpcgen will generate a header file in
proto.h, XDR routines in proto_xdr.c, server-side stubs in proto_svc.c, and client-side
stubs in proto_clnt.c. With the -T option, it will also generate the RPC dispatch table in
proto_tbl.i. With the -Sc option, it will also generate sample code which would illustrate
how to use the remote procedures on the client side. This code would be created in
proto_client.c. With the -Ss option, it will also generate a sample server code which would
illustrate how to write the remote procedures. This code would be created in
The server created can be started both by the port monitors (for example, inetd or listen)
or by itself. When it is started by a port monitor, it creates servers only for the trans-
port for which the file descriptor 0 was passed. The name of the transport must be speci-
fied by setting up the environmental variable PM_TRANSPORT. When the server generated by
rpcgen is executed, it creates server handles for all the transports specified in NETPATH
environment variable, or if it is unset, it creates server handles for all the visible
transports from /etc/netconfig file.
Note: the transports are chosen at run time and not at compile time. When the server is
self-started, it backgrounds itself by default. A special define symbol RPC_SVC_FG can be
used to run the server process in foreground.
The second synopsis provides special features which allow for the creation of more sophisti-
cated RPC servers. These features include support for user provided #defines and RPC dis-
patch tables. The entries in the RPC dispatch table contain:
+ pointers to the service routine corresponding to that procedure,
+ a pointer to the input and output arguments,
+ the size of these routines
A server can use the dispatch table to check authorization and then to execute the service
routine; a client library may use it to deal with the details of storage management and XDR
The other three synopses shown above are used when one does not want to generate all the
output files, but only a particular one. Some examples of their usage is described in the
EXAMPLES section below. When rpcgen is executed with the -s option, it creates servers for
that particular class of transports. When executed with the -n option, it creates a server
for the transport specified by netid. If infile is not specified, rpcgen accepts the stan-
The C preprocessor, cpp(1) is run on the input file before it is actually interpreted by
rpcgen For each type of output file, rpcgen defines a special preprocessor symbol for use by
the rpcgen programmer:
RPC_HDR defined when compiling into header files
RPC_XDR defined when compiling into XDR routines
RPC_SVC defined when compiling into server-side stubs
RPC_CLNT defined when compiling into client-side stubs
RPC_TBL defined when compiling into RPC dispatch tables
Any line beginning with '%' is passed directly into the output file, uninterpreted by
For every data type referred to in infile rpcgen assumes that there exists a routine with
the string ``xdr_'' prepended to the name of the data type. If this routine does not exist
in the RPC/XDR library, it must be provided. Providing an undefined data type allows cus-
tomization of XDR routines.
-a Generate all the files including sample code for client and server side.
-A Generate an svc_caller() function.
-b Compile stubs in "backwards compatible" mode, disabling support for transport-inde-
pendent RPC. The -b should always be specified when generating files for NetBSD,
since there is no transport-independent RPC support in NetBSD.
-c Compile into XDR routines.
-C Generate code in ANSI C. This option also generates code that could be compiled
with the C++ compiler.
Define a symbol name. Equivalent to the #define directive in the source. If no
value is given, value is defined as 1. This option may be specified more than once.
-h Compile into C data-definitions (a header file). The -T option can be used in con-
junction to produce a header file which supports RPC dispatch tables.
Size to decide when to start generating inline code. The default size is 3.
-I Support inetd(8) in the server side stubs. Servers generated using this flag can
either be standalone or started from inetd(8). If a server is started as stand-
alone, then it places itself in the background, unless RCP_SVC_FG is defined, or the
server is compiled without -I.
By default, services created using rpcgen wait 120 seconds after servicing a request
before exiting. That interval can be changed using the -K flag. To create a server
that exits immediately upon servicing a request, ``-K 0'' can be used. To create a
server that never exits, the appropriate argument is ``-K -1''.
When monitoring for a server, some port monitors, like the AT&T System V Release 4
UNIX utility listen, always spawn a new process in response to a service request.
If it is known that a server will be used with such a monitor, the server should
exit immediately on completion. For such servers, rpcgen should be used with ``-K
-l Compile into client-side stubs. inetd(8).
-I Compile stubs meant for use in programs started by inetd(8).
-L Server errors will be sent to syslog instead of stderr.
-m Compile into server-side stubs, but do not generate a main() routine. This option
is useful for doing callback-routines and for users who need to write their own
main() routine to do initialization.
-M Generate thread-safe stubs. This alters the calling pattern of client and server
stubs so that storage for results is allocated by the caller. Note that all compo-
nents for a particular service (stubs, client and service wrappers, etc.) must be
built either with or without the -M flag.
-N Use the newstyle of rpcgen. This allows procedures to have multiple arguments. It
also uses the style of parameter passing that closely resembles C. So, when passing
an argument to a remote procedure you do not have to pass a pointer to the argument
but the argument itself. This behaviour is different from the oldstyle of rpcgen
generated code. The newstyle is not the default case because of backward compati-
Compile into server-side stubs for the transport specified by netid. There should
be an entry for netid in the netconfig database. This option may be specified more
than once, so as to compile a server that serves multiple transports.
Specify the name of the output file. If none is specified, standard output is used
(-c -h -l -m -n -s modes only)
Specify the transport for the server-side stubs. netid should be defined in
netconfig(5). This option can be repeated in order to support more than one trans-
Compile into server-side stubs for all the transports belonging to the class
nettype. The supported classes are netpath, visible, circuit_n, circuit_v,
datagram_n, datagram_v, tcp, and udp [see rpc(3) for the meanings associated with
these classes. Note: BSD currently supports only the tcp and udp classes]. This
option may be specified more than once. Note: the transports are chosen at run time
and not at compile time.
-Sc Generate sample code to show the use of remote procedure and how to bind to the
server before calling the client side stubs generated by rpcgen.
-Ss Generate skeleton code for the remote procedures on the server side. You would need
to fill in the actual code for the remote procedures.
-t Compile into RPC dispatch table.
-T Generate the code to support RPC dispatch tables.
-v Display the version number.
Specify the directory where rpcgen looks for the C pre-processor.
The options -c, -h, -l, -m, -s, and -t are used exclusively to generate a particular type of
file, while the options -D and -T are global and can be used with the other options.
If the RPCGEN_CPP environment variable is set, its value is used as the pathname of the C
preprocessor to be run on the input file.
The RPC Language does not support nesting of structures. As a work-around, structures can
be declared at the top-level, and their name used inside other structures in order to
achieve the same effect.
Name clashes can occur when using program definitions, since the apparent scoping does not
really apply. Most of these can be avoided by giving unique names for programs, versions,
procedures and types.
The server code generated with -n option refers to the transport indicated by netid and
hence is very site specific.
$ rpcgen -T prot.x
generates the five files: prot.h, prot_clnt.c, prot_svc.c, prot_xdr.c and prot_tbl.i.
The following example sends the C data-definitions (header file) to standard output.
$ rpcgen -h prot.x
To send the test version of the -DTEST, server side stubs for all the transport belonging to
the class datagram_n to standard output, use:
$ rpcgen -s datagram_n -DTEST prot.x
To create the server side stubs for the transport indicated by netid tcp, use:
$ rpcgen -n tcp -o prot_svc.c prot.x
The -M option was first implemented in RedHat Linux, and was reimplemented by Charles M.
Hannum in NetBSD 1.6.
BSD January 19, 2008 BSD