rpcgen - an RPC protocol compiler
rpcgen [-Dname[=value]] [-T] [-K secs] infile
rpcgen -c|-h|-l|-m|-M|-t [-o outfile ] infile
rpcgen [-I] -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 gener-
ates 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 dis-
patch 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
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
transport for which the file descriptor 0 was passed. The name of the transport must be
specified by setting up the environmental variable PM_TRANSPORT. When the server gener-
ated 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 built for a port monitor (rpcgen -I), and that the server is self-started, it back-
grounds 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 sophis-
ticated RPC servers. These features include support for user provided #defines and RPC
dispatch tables. The entries in the RPC dispatch table contain:
o pointers to the service routine corresponding to that procedure,
o a pointer to the input and output arguments
o 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 data conversion.
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
EXAMPLE 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 standard input.
The C preprocessor, cc -E [see cc(1)], is run on the input file before it is actually
interpreted by rpcgen. For each type of output file, rpcgen defines a special preproces-
sor 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 rpc-
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.
The following options are available:
-a Generate all the files including sample code for client and server side.
-b This generates code for the SunOS4.1 style of rpc. It is for backward compatibil-
ity. This is the default.
-5 This generates code for the SysVr4 style of rpc. It is used by the Transport Inde-
pendent RPC that is in Svr4 systems. By default rpcgen generates code for SunOS4.1
stype of rpc.
-c Compile into XDR routines.
-C Generate code in ANSI C. This option also generates code that could be compiled
with the C++ compiler. This is the default.
-k Generate code in K&R C. The default is ANSI C.
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
-h Compile into C data-definitions (a header file). -T option can be used in conjunc-
tion to produce a header file which supports RPC dispatch tables.
-I Generate a service that can be started from inetd. The default is to generate a
static service that handles transports selected with -s. Using -I allows starting
a service by either method.
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 portmonitors, like listen(1M), 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 -1.
-l Compile into client-side stubs.
-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 multithread-safe stubs for passing arguments and results between rpcgen-
generated code and user written code. This option is useful for users who want to
use threads in their code.
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.
-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-
Specify the name of the output file. If none is specified, standard output is used
(-c, -h, -l, -m, -n, -s, -Sc, -Sm, -Ss, and -t modes only).
Compile into server-side stubs for all the transports belonging to the class net-
type. The supported classes are netpath, visible, circuit_n, circuit_v, data-
gram_n, datagram_v, tcp, and udp [see rpc(3N) for the meanings associated with
these 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.
-Sm Generate a sample Makefile which can be used for compiling the application.
-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.
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.
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.
The following example:
$ 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 the 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