PPWIZARD is a free preprocessor for HTML, REXX, Visual Basic or any text files.
#ifndef |
A #ifndef command (like #if and #ifdef) can be used to conditionally include lines of text, this can be any other type of line or command except #elseif or #endif.
#if commands can be nested to any level and there need not be any lines between a #if command and a #endif or #elseif command.
Note that this command only checks on a single variable, for more complex requirements you will need to use a #if command along with calls to the Defined() routine. For performance reasons it is recommended that you use #ifdef and #ifndef commands where possible.
Syntax |
[WhiteSpace]#ifndef MacroName
The "MacroName" specifies the name of a macro that should NOT exist for the test to evaluate to true.
Example |
#define Fred FredsValue #ifndef Fred ... #endif