Name format of generation files

The following syntax describes how to form absolute and relative references to generation data groups (GDGs) and generation files.

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GDG and GDS syntax

>>-gdgBaseName-+------------------------+----------------------><
               +-.gxxxxvyy--------------+   
               '-(--+-*------------+--)-'   
                    +-+-----+--mmm-+        
                    | '- - -'      |        
                    '- +nnnn-------'        

gdgBaseName
The name of the generation data group and the base name of the GDG catalog (a binary file gdgBaseName.catalogue in the AIX native file system).

gdgBaseName can be any valid file name. However, avoid specifying a base name that looks like an absolute or relative reference, for example, my(+1)Base.

.gxxxxvyy
An absolute generation and version number that identify a specific generation, where:
  • xxxx is an unsigned 4-digit decimal number from 0001 through 9999, inclusive.
  • yy is 00. 00 is the only version number that is supported. Nonzero version numbers are ignored.

An absolute name is thus of the form gdgBaseName.gxxxxvyy.

*
A relative suffix that designates an entire group. All generation files in a group are concatenated in generation order, the most current generation first.

A reference to the entire group is of the form gdgBaseName(*) or gdgBaseName.

mmm
A relative generation number from 0 to 999, inclusive, that identifies a specific generation. The number refers to the current generation (0), the previous or less current generation (1) or (-1), and so forth. The negative sign is optional.

It is an error to refer to a nonexistent generation.

A relative name for an existing generation is thus of the form gdgBaseName(mmm) or gdgBaseName(-mmm).

+nnnn
A positive relative generation number from 1 to 9999, inclusive, that typically identifies a generation to be created and added to a GDG.

A number greater than 1 can cause generation numbers to be skipped. For example, if only one generation exists and gdgBaseName(+3) is specified, two generations are skipped.

It is not an error to open for input a reference such as gdgBaseName(+1234) if the reference resolves to an existing file in the group.

related concepts  
Generation data groups

related tasks  
Using generation data groups