It must be one of the following characters (not case-sensitive):
N - no EXEC SQL support is present
Y - the user has provided for EXEC SQL support by an
explicit PREPROCESS directive or the SQL directive.
X - the XDB EXEC SQL preprocessor is to be invoked by
the TX preprocessor
G - the GUPTA EXEC SQL preprocessor is to be invoked by
the TX preprocessor
0 - not specified