Added if-statement documentation.

diff --git a/src/cf.data.pre b/src/cf.data.pre
index eb50206d5a3c235f68929578c14a64a2f5c02e3f..8b780b1e37a54b9c736f1b8ba7c191796dc89b3a 100644 (file)
--- a/src/cf.data.pre
+++ b/src/cf.data.pre
@@ -59,6 +59,31 @@ COMMENT_START
   configuration files.
 
 
+  Conditional configuration
+
+       If-statements can be used to make configuration directives
+       depend on conditions:
+
+           if <CONDITION>
+               ... regular configuration directives ...
+           [else
+               ... regular configuration directives ...]
+           endif
+
+       The else part is optional. The keywords "if", "else", and "endif"
+       must be typed on their own lines, as if they were regular
+       configuration directives.
+
+       These individual conditions types are supported:
+
+           true
+               Always evaluates to true.
+           false
+               Always evaluates to false.
+           <integer> = <integer>
+               Equality comparison of two integer numbers.
+
+
   SMP-Related Macros
 
        The following SMP-related preprocessor macros can be used.