Header files included in your program

The Informix® ESQL/C preprocessor automatically includes the following Informix ESQL/C header files in your program:
  • The sqlhdr.h file provides cursor-related structures for your Informix ESQL/C program.

    This header file automatically includes the sqlda.h and ifxtypes.h header files.

  • The sqlca.h file, which allows your program to check the success or failure of your Informix ESQL/C statements with the SQLSTATE or SQLCODE variable
Restriction: Although you can now use an ANSI C compiler, the Informix ESQL/C preprocessor does not fully support ANSI C, so you might not be able to preprocess all programs that follow the ANSI C standards.
To include any of the other header files in your Informix ESQL/C program, you must use the include preprocessor directive. However, you only need to include the Informix ESQL/C header file if your program refers to the structures or the definitions that the header file defines. For example, if your program accesses datetime data, you must include the datetime.h header file, as follows:
EXEC SQL include datetime.h;
Make sure to terminate the line of code with a semicolon. Some additional examples follow:
EXEC SQL include varchar.h;
EXEC SQL include sqlda;
$include sqlstype;
Tip: You do not have to enter the .h file extension for the Informix ESQL/C header file; the esql preprocessor assumes a .h extension.