[CMake] if(string MATCHES regex) question

[Marcel Loose]

Wow,

So this really is ancient code! 
Thanks for the explanation.

Best regards,
Marcel Loose

On Fri, 2009-07-03 at 07:59 -0400, Brad King wrote:
> Eric Noulard wrote:
> >> If so, I still don't quite get the usage pattern in, e.g.,
> >> CheckIncludeFile.cmake. What are they trying to check?
> > 
> > Better ask the author of this file :-)
> 
> This was a hack left from before the 'DEFINED' option was
> available from the if() command.  The code
> 
>    if(VAR MATCHES "^VAR$")
> 
> is almost equivalent to
> 
>    if(NOT DEFINED VAR)
> 
> because the if() command replaces VAR with ${VAR} implicitly
> when VAR is defined (but '^VAR$' is not defined and does not
> get replaced).  The implicit conversion is left from *very*
> early CMake when there was no ${} syntax.
> 
> -Brad