xHarbour Reference Documentation > Function Reference

HB_IsNull()

Tests if the value returned by an expression is empty.

Syntax

HB_IsNull( <expression> ) --> lIsNull

Arguments

<expression>

This is an expression of data type Array, Character or Hash. If a value of a different data type is passed, a runtime error is raised.

Return

The function returns .T. (true) if the value returned by <expression> is an empty array, character string or hash, otherwise .F. (false) is returned.

Description

Function HB_IsNull() is used to test if a variable contains an empty value of data type Array, Character or Hash. The function can be used as a replacement for the expression: Len(<expression>)==0.

Info

See also:	HB_IsArray(), HB_IsBlock(), HB_IsByRef(), HB_IsDate(), HB_IsHash(), HB_IsLogical(), HB_IsMemo(), HB_IsNIL(), HB_IsNumeric(), HB_IsObject(), HB_IsPointer(), HB_IsString(), Type(), Valtype()
Category:	Debug functions , Logical functions , xHarbour extensions
Source:	rtl\valtype.c
LIB:	xhb.lib
DLL:	xhbdll.dll