INFORMIX-ESQL/C Programmer's Manual Programming with INFORMIX-ESQL/C

When you install INFORMIX-ESQL/C, the installation script stores the header files in the $INFORMIXDIR/incl/esql directory on a UNIX operating system and in the %INFORMIXDIR%\incl\esql directory in a Windows environment.

Figure 1-17 shows the header files provided with the ESQL/C product.

Figure 1-18 on page 1-40 shows the ESQL/C header files specific to Dynamic Server with UD Option.

Figure 1-18
ESQL/C Header Files for Dynamic Server with UD Option

Header File	Contents	Additional Information
collct.h	Definitions of data structures for complex types in ESQL/C	Chapter 9
ifxgls.h	Function prototypes for the GLS Application Programming Interface For internal ESQL/C use only.	None
int8.h	Definition of the structure that stores the INT8 data type	The int8 Data Type

Figure 1-19 shows the ESQL/C header files specific to Windows environments.

Figure 1-19
ESQL/C Header Files for Windows Environments

Header File	Contents	Additional Information
sqlproto.h	Function prototypes of all ESQL/C library functions for use with source that is not fully ANSI C compliant	Declaring Function Prototypes
ifxcexp.c	Contains the C code to export the addresses of all C runtime routines that the ESQL client-interface DLL uses	Using the Same Runtime Routines for Version Independence
login.h	The definition of the InetLogin and HostInfoStruct structures, which enable you to customize configuration information for the application Because this file does not contain ESQL statements, you do not need to include it with the ESQL include directive. Use instead the C #include preprocessor directive.	Fields of the InetLogin Structure

Declaring Function Prototypes

ESQL/C provides the sqlproto.h header file to declare function prototypes for all ESQL/C library functions. These function prototypes are required in an ESQL/C source file that you compile with an ANSI C compiler. By default, the esql command processor does not include function-prototype declarations. Having the processor include the ANSI-compliant function prototypes for the ESQL/C functions prevents an ANSI C compiler from generating warnings.

Warning: Although you can use an ANSI C compiler, the 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.

Because the sqlproto.h file does not contain any ESQL/C statements, you can include this file in either of the following ways:

• With the ESQL/C include preprocessor directive:
EXEC SQL include sqlproto;
• With the C #include preprocessor directive:
#include "sqlproto.h";

The ESQL/C preprocessor automatically includes the following ESQL/C header files in your program:

• The sqlhdr.h file provides cursor-related structures for your ESQL/C program.

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

• The sqlca.h file, which allows your program to check the success or failure of your ESQL/C statements with the SQLSTATE or SQLCODE variable

Warning: Although you can now use an ANSI C compiler, the 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 ESQL/C program, you must use the include preprocessor directive. However, you only need to include an 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 an ESQL/C header file; the esql preprocessor assumes a .h extension. 

For information on the include directive, see The include Directive.