Writing programs

Development and runtime character set must match

When writing a form or program source file, you use a specific character set. This character set depends upon the text editor or operating system settings you are using on the development platform. For example, when writing a string constant in a .4gl module, containing Arabic characters, you probably use the ISO-8859-6 character set. The character set used at runtime (during program execution) must match the character set used to write programs.

At runtime, a Genero program can only work in a specific character set. However, by using localized strings, you can start multiple instances of the same compiled program using different locales. For a given program instance the character set used by the strings resource files must correspond to the locale. Make sure the string identifiers use ASCII only.

Byte length semantics and substring expressions

When using Byte Length Semantics (BLS), all character positions in strings are actually byte positions. In a multibyte environment, if you don't pay attention to this, you can end up with invalid characters in strings. For example, an expression using a subscript operator [x,y] might refer to a byte position which is in fact in the middle of a multibyte character. If possible, use Character Length Semantics (CLS) with a multibyte locale to avoid such problems, or use only STRING methods to parse character strings.