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v The code-set-conversion object file is a compiled form of the code-set-conversion
information.
IBM Informix products use the object file to obtain code-set-conversion
information quickly. Object code-set-conversion files have a .cvo file extension.
The header of the code-set-conversion source file (.cv) lists the two code sets that
it converts and the direction of the conversion.
Code-set-conversion file names
To conform to DOS 8.3 naming conventions, GLS code-set-conversion files use a
condensed form of the code-set names, code1code2, in their file names.
The eight-character name of each code-set-conversion file is derived from the
hexadecimal representation of the code-set numbers of the source code set (code1)
and the target code set (code2).
For example, the ISO8859-1 code set has an IBM CCSID number of 819 in decimal
and 0333 in hexadecimal. The IBM CCSID 437 code set, a common IBM UNIX code
set, has a hexadecimal value of 01b5. Therefore, the 033301b5.cv
code-set-conversion file describes the conversion from the CCSID 819 code set to
the CCSID 437 code set.
Required for code-set conversion
IBM Informix products use the Code-Set Name-Mapping file to translate between
code-set names and the more compact code-set numbers. You can use the registry
file to find the hexadecimal values that correspond to code-set names or code-set
numbers.
Most code-set conversion requires two code-set-conversion files. One file supports
conversion of characters in code set A to their counterparts in code set B. Another
supports the conversion in the return direction (from B to A). Such conversions are
called two-way code-set conversions. For example, the code-set conversion between
the CCSID 437 code set (hexadecimal 01b5 code number) and the CCSID 819 code
set (or ISO8859-1 with a hexademical 0333 code number) requires the following
two code-set-conversion files:
v The 01b50333.cv file describes the mappings to use when IBM Informix products
convert characters in the CCSID 437 code set to those in the ISO8859-1 code set.
v The 033301b5.cv file describes the mappings to use when IBM Informix products
convert characters in the ISO8859-1 code set to those in the CCSID 437 code set.
To be able to convert between these two code sets, an IBM Informix product must
be able to locate both these code-set-conversion object files. Performing the
conversion on only one direction would result in mismatched characters. For more
information about mismatched characters, see “Perform code-set conversion” on
page 1-29.
The following table shows some of the code-set conversions that IBM Informix
products can support, along with their associated code-set-conversion source file
names.
Source code set
Target code set
Code-set-conversion
source file
ISO8859-1
Windows Code Page 1252
033304e4.cvo
Windows Code Page 1252
ISO8859-1
04e40333.cvo
Appendix A. Manage GLS files
A-9