#ifndef

#ifndef — Conditional reading of code.

Description

If the specified macro is not defined then #ifndef can incorporate text into an orchestra upto the next #end. This is similar to, but independent of, the macro system in the score language.

Syntax

#ifndef NAME
....
#else 
....
#end 

Performance

Note that the #ifndef can be nested, like in the C preprocessor language.

Examples

Here is a simple example of the conditional.

Example 18. Simple example of the #ifndef form.

          #define final ##
          instr 1
          #ifndef final
          print "calling oscil"
          #end
          a1   oscil 32000,440,1
          out  a1
        endin


See Also

$NAME, #define, #ifdef.

Credits

Author: John ffitch
University of Bath/Codemist Ltd.
Bath, UK
April 2005

New in Csound5 (and 4.23f13)