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Client APIs and toolsYou can use the HCL OneDB™ implementation of client APIs to develop applications for HCL OneDB™ database servers.
ESQL/C GuideThe HCL OneDB™ ESQL/C Programmer's Manual explains how to use , the HCL OneDB™ implementation of Embedded Structured Query Language (SQL) for C (ESQL/C), to create client applications with database-management capabilities.
AppendixesThis section contains additional reference information.
The ESQL/C function libraryThese topics describe the syntax and behavior of all the library functions provided with HCL® OneDB® ESQL/C.
The ifx_var_isnull() functionThe ifx_var_isnull() function checks whether an lvarchar or var binary host variable contains a null value.

The ifx_var_isnull() function

The ifx_var_isnull() function checks whether an lvarchar or var binary host variable contains a null value.

Syntax

var binary

mint ifx_var_isnull(var_bin)
   var binary **var_bin;

lvarchar

mint ifx_var_isnull(lvar)
   lvarchar **lvar;

var_bin: The address of the var binary host variable.
lvar: The address of the lvarchar pointer host variable.

Usage

The ifx_var_isnull() function checks for a null value in an lvarchar or var binary host variable. To determine whether the host variable of any other data type contains null, use the risnull() library function.

Return codes

0: The opaque-type data is not a null value.
1: The opaque-type data is a null value.