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rpcgen - an RPC protocol compiler


See Also


rpcgen infile rpcgen [-a] [-b] [-C] [ -D name [=value] ] [-i size] [-I-P [-K seconds]] [-L] [-M] [-N] [-T] [-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 three 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.

The rpcgen utility 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 makefile.proto.

If option -I is set, the server created can be started both by the port monitors (for example, inetd(8)) 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 may be specified by setting up the environment variable NLSPROVIDER. 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 sophisticated RPC servers. These features include support for user provided #defines and RPC dispatch 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 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.

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. To specify the path name of the C preprocessor use -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(3) routines.


The following options are available:
-a Generate all files, including sample files.
-b Backward compatibility mode. Generate transport specific RPC code for older versions of the operating system.
-c Compile into XDR routines.
-C Generate header and stub files which can be used with ANSI C compilers. Headers generated with this flag can also be used with C++ programs.
-D name
-D name=value
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). -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 5.

Note: in order to provide backwards compatibility with the older rpcgen on the
.Fx platform, the default is actually 0 (which means that inline code generation is disabled by default). You must specify a non-zero value explicitly to override this default.

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

If there are no pending client requests, the inetd(8) servers exit after 120 seconds (default). The default can be changed with the -K option. All the error messages for inetd(8) servers are always logged with syslog(3).

Note: Contrary to some systems, in
.Fx this option is needed to generate servers that can be invoked through portmonitors and inetd(8).

-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 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 0.

-l Compile into client-side stubs.
-L When the servers are started in foreground, use syslog(3) to log the server errors instead of printing them on the standard error.
-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. However, the rpc_svc_calls(3) functions are not yet MT-safe, which means that rpcgen generated server-side code will not be MT-safe.
-N Allow 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
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.
-o outfile
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).
-P Compile support for port monitors in the server side stubs.

Note: Contrary to some systems, in
.Fx this option is needed to generate servers that can be monitored.

If the -I option has been specified, -P is turned off automatically.

-s nettype
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). This option may be specified more than once. Note: the transports are chosen at run time and not at compile time.
-Sc Generate sample client code that uses remote procedure calls.
-Sm Generate a sample Makefile which can be used for compiling the application.
-Ss Generate sample server code that uses remote procedure calls.
-t Compile into RPC dispatch table.
-T Generate 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.

-Y pathname
Give the name of the directory where rpcgen will start looking for the C-preprocessor.


The following example:

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.

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

example% rpcgen -h prot.x

To send the test version of the -D TEST, 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

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

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


cc(1), rpc(3), rpc_svc_calls(3), syslog(3), xdr(3), inetd(8)
.Rs The rpcgen chapter in the NETP manual

Created by Blin Media, 2008-2013