Is Informix ANSI ?

• Is the Informix standard ANSI?
  
• Does it accept the function CAST()?
  
• What is the largest size char that I can declare?

Answer:
Informix conforms to ANSI SQL-92 Entry Level, with some support for advanced features.

There is no CAST() function.

The maximum character size according to the last SQL manual is 32,767 bytes.