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rpcgen - an RPC protocol compiler


rpcgen infile

rpcgen [-a] [-A] [-b] [-C] [-D name [= value]] [-i size]
[-I [-K seconds]] [-L] [-M] [-N] [- T] [-v]
[-Y pathname] infile

rpcgen [-c | -h | -l | -m | -t | -Sc | -Ss | -Sm]
[-o outfile] [infile]

rpcgen [-s nettype] [-o outfile] [infile]

rpcgen [-n netid] [-o outfile] [infile]


The rpcgen utility 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).

The rpcgen utility is normally used as in the first synopsis where it
takes an input file and generates four output files. If the infile is
named proto.x, then rpcgen generates a header 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 also generates the RPC dispatch
table in proto_tbl.i.

rpcgen can also generate sample client and server files that can be
customized to suit a particular application. The -Sc, -Ss, and -Sm
options generate sample client, server and makefile, respectively. The
-a option generates all files, including sample files. If the infile is
proto.x, then the client side sample file is written to proto_client.c,
the server side sample file to proto_server.c and the sample makefile to

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
environment variable PM_TRANSPORT. When the server generated by rpcgen is
executed, it creates server handles for all the transports specified in
the NETPATH environment variable, or if it is unset, it creates server
handles for all the visible transports from the /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

The second synopsis provides special features which allow for the
creation of more sophisticated 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

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 can use the dispatch table
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. See the
EXAMPLES section below for examples of rpcgen usage. 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.

All the options mentioned in the second synopsis can be used with the
other three synopses, but the changes are made only to the specified
output file.

The C preprocessor cc -E 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:

defined when compiling into headers

defined when compiling into XDR routines

defined when compiling into server-side stubs

defined when compiling into client-side stubs

defined when compiling into RPC dispatch tables

Any line beginning with ``%'' is passed directly into the output file,
uninterpreted by rpcgen, except that the leading ``%" is stripped off. To
specify the path name of the C preprocessor, use the -Y flag.

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 customization of XDR

Server Error Reporting

By default, errors detected by proto_svc.c is reported to standard error
and/or the system log.

This behavior can be overridden by compiling the file with a definition
of RPC_MSGOUT, for example, -DRPC_MSGOUT=mymsgfunc. The function
specified is called to report errors. It must conform to the following
printf-like signature:

extern void RPC_MSGOUT(const char *fmt, ...);


The following options are supported:

Generates all files, including sample files.

Enables the Automatic MT mode in the server main
program. In this mode, the RPC library automatically
creates threads to service client requests. This
option generates multithread-safe stubs by implicitly
turning on the -M option. Server multithreading modes
and parameters can be set using the rpc_control(3NSL)
call. rpcgen generated code does not change the default
values for the Automatic MT mode.

Backward compatibility mode. Generates transport-
specific RPC code for older versions of the operating

Compiles into XDR routines.

Generates header and stub files which can be used with
ANSI C compilers. Headers generated with this flag can
also be used with C++ programs.

Defines a symbol name. Equivalent to the #define
directive in the source. If no value is given, value is
defined as 1. This option can be specified more than

Compiles into C data-definitions (a header). The -T
option can be used in conjunction to produce a header
which supports RPC dispatch tables.

-i size
Size at which to start generating inline code. This
option is useful for optimization. The default size is

Compiles support for inetd(8) in the server side stubs.
Such servers can be self-started or can be started by
inetd. 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, or
the user can simply compile without the -I option.

If there are no pending client requests, the inetd
servers exit after 120 seconds (default). The default
can be changed with the -K option. All of the error
messages for inetd servers are always logged with

Note: This option is supported for backward
compatibility only. It should always be used in
conjunction with the -b option which generates backward
compatibility code. By default (that is, when -b is not
specified), rpcgen generates servers that can be
invoked through portmonitors.

-K seconds
By default, services created using rpcgen and invoked
through port monitors 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, use -K 0. To
create a server that never exits, the appropriate
argument is -K -1.

When monitoring for a server, some portmonitors, like
listen(8), always spawn a new process in response to a
service request. If it is known that a server are used
with such a monitor, the server should exit immediately
on completion. For such servers, rpcgen should be used
with -K 0.

Compiles into client-side stubs.

When the servers are started in foreground, uses
syslog(3C) to log the server errors instead of printing
them on the standard error.

Compiles 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.

Generates 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.

This option 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 can pass the argument
itself. This behavior is different from the old style
of rpcgen-generated code. To maintain backward
compatibility, this option is not the default.

-n netid
Compiles into server-side stubs for the transport
specified by netid. There should be an entry for netid
in the netconfig database. This option can be specified
more than once, so as to compile a server that serves
multiple transports.

-o outfile
Specifies 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).

-s nettype
Compiles 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(3NSL) for the
meanings associated with these classes). This option
can be specified more than once. Note: The transports
are chosen at run time and not at compile time.

Generates sample client code that uses remote procedure

Generates a sample Makefile which can be used for
compiling the application.

Generates sample server code that uses remote procedure

Compiles into RPC dispatch table.

Generates the code to support RPC dispatch tables.

The options -c, -h, -l, -m, -s, -Sc, -Sm, -Ss, 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.

Displays the version number.

-Y pathname
Gives the name of the directory where rpcgen starts
looking for the C preprocessor.


The following operand is supported:

input file


Example 1: Generating the output files and dispatch table

The following entry

example% rpcgen -T prot.x

generates all the five files: prot.h, prot_clnt.c, prot_svc.c,
prot_xdr.c, and prot_tbl.i.

Example 2: Sending headers to standard output

The following example sends the C data-definitions (header) to the
standard output:

example% rpcgen -h prot.x

Example 3: Sending a test version

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:

example% rpcgen -s datagram_n -DTEST prot.x

Example 4: Creating server side stubs

To create the server side stubs for the transport indicated by netid tcp,

example% rpcgen -n tcp -o prot_svc.c prot.x


Successful operation.

An error occurred.


syslog(3C), rpc(3NSL), rpc_control(3NSL), rpc_svc_calls(3NSL),
netconfig(5), attributes(7), inetd(8), listen(8)

The rpcgen chapter in the ONC+ Developer's Guide manual.

December 16, 2013 RPCGEN(1)