The X/Open standards

The -xopen option tells the IBM® Informix® ESQL/C preprocessor that your program uses X/Open standards.

When you specify this option, the preprocessor performs the following two tasks:

It checks for Informix extensions to X/Open-standard syntax.
If you include Informix extensions to X/Open-standard syntax in your code, the preprocessor generates warning messages.
It uses the X/Open set of codes for SQL data types.
Informix ESQL/C uses these codes in a dynamic management structure (a system-descriptor area or an sqlda structure) to indicate column data types. Informix defines these codes in the sqlxtype.h header file.

If you use X/Open SQL in the Informix ESQL/C program, you must recompile any other source files in the same application with the -xopen option.

If you compile a program with both the -xopen and -ansi options, the Informix ESQL/C preprocessor generates warning messages for Informix extensions to both X/Open and ANSI SQL syntax.