Programming with Remote Procedure Calls (RPC)

Using preprocessing directives

The rpcgen compiler supports C and other preprocessing features.

C-preprocessing is performed on rpcgen input files before they are compiled. All C-preprocessing directives are valid within a .x file. Five symbols may be defined by rpcgen, depending on the type of output file being generated. The symbols are:

Symbol Usage

RPC_HDR Header file output

RPC_XDR XDR routine output

RPC_SVC Server skeleton output

RPC_CLNT Client stub output

RPC_TBL Index table output

Symbol	Usage
RPC_HDR	Header file output
RPC_XDR	XDR routine output
RPC_SVC	Server skeleton output
RPC_CLNT	Client stub output
RPC_TBL	Index table output

The rpcgen compiler provides an additional preprocessing feature: any line that begins with a percent sign (%) is passed directly into the output file, without any interpretation of the line.

NOTE: The % feature is not always useful, owing to a limitation: The rpcgen compiler may not place the lines where the programmer intended.

This is a simple example that illustrates rpcgen preprocessing features:

   /*
    * time.x: Remote time protocol
    */
   program TIMEPROG {
   	version TIMEVERS {
   			unsigned int TIMEGET(void) = 1;
   	} = 1;
   } = 0x20000044;
   
   #ifdef RPC_SVC
   %int *
   %timeget_1()
   %{
   %	static int thetime;
   %
   %	thetime = time(0);
   %	return (&thetime);
   %}
   #endif