Delphi in a Nutshell

Name

High Function

Syntax

function High(Type or variable): Ordinal type;

Description

The High function returns the largest value of an enumerated type, the upper bound of an array index, or the same information for a variable of ordinal or array type.

High is built into the compiler and is not a real function.

Tips and Tricks

• In a for loop, subrange type declaration, or any other situation where you use the limits of an ordinal or array type, always use the High function instead of referring explicitly to the high ordinal value. A future version of your code might extend the type, and you don’t want to scramble through all your code looking for explicit references to an enumerated literal that should really have been calls to the High function.

• Calling High for a ShortString returns the highest index for the string type. You cannot call High for an AnsiString or WideString.

• High for an open array parameter is always the length of the array minus one, regardless of the type or range of the actual array argument.

Example

// See the example of the asm keyword for the GetCpuId function. // Get the CPU identification, and write it to Output. procedure WriteCpuId; const CpuTypes: array[TCpuType] of string = ('Original', 'Overdrive', 'Dual', '?'); var ID: TCpuId; F: TCpuFeature; begin if not GetCpuId(ID) then WriteLn('No CPUID instruction') else begin WriteLn(ID.Vendor, ' ', CpuTypes[ID.CpuType]); WriteLn('Family: ', ID.Family); WriteLn('Model: ', ID.Model); WriteLn('Stepping: ', ID.Stepping); ...