Using uuidgen to Create an IDL Template


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Programming a BEA Tuxedo Application Using TxRPC

A Universal Unique Identifier (UUID) is used to uniquely identify an interface. The uuidgen command is used to generate UUIDs. The output might look something like the following.

$ uuidgen -i > simp.idl
$ cat simp.idl
[uuid(816A4780-A76B-110F-9B3F-930269220000)]
interface INTERFACE
{
}

This template is then used to create the IDL input file for the application (adding type definitions, constants, and operations).

If both the BEA Tuxedo and DCE uuidgen(1) commands are available, the DCE command can and should be used to generate the template (the DCE version will most likely have a machine-specific approach to getting the node address, as described below).

The BEA Tuxedo system uuidgen command is similar to the DCE command with the exception that the -s option (which generates a UUID string as an initialized C structure), and the -t option (which translates an old style UUID string to the new format) are not supported. See the uuidgen(1) reference page for details of the interface.

The uuidgen command requires a 48-bit node address as described in ISO/IEC 8802-3 (ANSI/IEEE 802.3). There is no platform-independent way to determine this value, and it may not be available at all on some machines (a workstation, for example). The following approach is used for the BEA Tuxedo system uuidgen command:

If the NADDR environment variable is set to a value of the form num.num.num.num.num.num where num is between 0 and 255, inclusive, it is taken to be an Internet-style address and converted to a 48-bit node address. This allows conformance with the use of the 8802-3 node address. It also allows users who do not have access to this address to use another value, most likely the Internet address (which is not the same as the 8802-3 address). If the Internet address is used, the last num.num should be 0.0 (because Internet addresses are only 32-bit addresses).
If the NADDR environment variable is not set and if the WSNADDR environment variable is set to a value of the form 0xnnnnnnnnnnnnnnnn it is taken to be a hexadecimal network address, as used in Workstation. Again note that this is not the 8802-3 address, and the last 16 bits will be treated as zeros.
If neither the NADDR nor the WSNADDR environment variable is set (and if not DOS, Windows, or OS/2), the uname for the machine is used to look up the machine entry in /etc/hosts to get the Internet-style address.
If the first three choices are not available, a warning is printed and 00.00.00.00.00.00 is used. This is not desirable because it reduces the chance of generating a unique UUID.