Programming Considerations

Compatibility vs. Native Mode

Compatibility mode allows you to run application programs compiled on an MPE V computer system on an MPE XL computer system without change. Native mode refers to application programs compiled and executed on an MPE XL computer system.

NetIPC applications written for MPE V based HP 3000s can be migrated to MPE XL HP 3000s (series 900s) and run in compatibility mode as follows. On the MPE-V system, use the MPE STORE command to save your program's object code. On the MPE XL system, use the MPE RESTORE command on your object code.

To take advantage of the optimizing compilers and improved performance on the XL, you must recompile your application program on the MPE XL system that will execute in native mode (NM). Some applications contain code that must be altered before migrating to native mode.

Application migration considerations are documented in the Application Migration Guide.

Example 2 in Chapter 4 “NetIPC Examples” shows the differences in declarations required for compiling a NetIPC program in compatibility mode and in native mode.

Option Variable

Many of the NetIPC intrinsics are option variable meaning they can be called with a variable number of parameters. Required parameters are listed in the discussion of each intrinsic. If you omit an optional parameter, the comma delimiter (,) is required to preserve parameter position.

For example, a call using IPCCONNECT could be entered as follows:

     IPCCONNECT(CALLDESC, DEST, , , VCDESC, RESULT)

In this example, note that following the parameter DEST, commas delimit the omitted optional parameters flags and opt.

Syntax

The syntax description provided for each NetIPC intrinsic is the syntax required for Pascal programs. Differences in parameter declarations for other languages (if any) are documented in Appendix E “C Program Language Considerations”

Capabilities

Some NetIPC intrinsics require special capabilities if you use the functions described below.

User-specified Protocol Addressing

NetIPC intrinsics IPCCONNECT, IPCCREATE, and IPCDEST allow you to specify protocol relative addresses. Addresses in the range 30767 to 32767 decimal (%74057 to %77777) can be used without special capabilities. In privileged programs you can specify protocol relative addresses between 1 and 30766 decimal (%1 and %74056).

	NOTE: The protocol relative address range 1 to 30766 decimal, (%1 to %74056) is administered by HP. Contact your HP representative before using an address within this reserved range.