This shows how to detect if your application is using FireMonkey (FMX) or VCL when using conditional compilation in a Delphi form
UPDATE – a better solution has been provided by a Rudy Velthuis. I recommend to use that instead of my original post. Ive provided examples based on his feedback. Thanks Rudy
-- Rudy Velthuis' updated solution
{$IF not declared(FireMonkeyVersion)}
ShowMessage('VCL');
{$ELSE}
ShowMessage('FMX');
{$IFEND}
-- Making it even simpler, this is the same code
-- with the "not" removed so the logic is flipped
{$IF declared(FireMonkeyVersion)}
ShowMessage('FMX');
{$ELSE}
ShowMessage('VCL');
{$IFEND}
-- a handy function that can be used in regular code
-- rather than conditional compilation
function IsFMX : boolean;
begin
{$IF declared(FireMonkeyVersion)}
result := TRUE;
{$ELSE}
result := FALSE;
{$IFEND}
end;
The following is my original post
{$IF FMX.Types.FireMonkeyVersion >= 0} // if FireMonkey
DoSomethingFMX;
{$ELSE} // its not FMX, so it must be VCL
DoSomethingVCL;
{$ENDIF}
Can I Reverse the logic ?
No, reversing the logic does not work. The reason for this is we are relying on the behaviour of Delphi conditional compile to return FALSE if the variable in the {$IF} does not exist.
To clarify … this works correctly
{$IF FMX.Types.FireMonkeyVersion >= 0} // if FireMonkey
ShowMessage ('FMX 1');
{$ELSE} // its not FMX, so it must be VCL
ShowMessage ('VCL 1');
{$ENDIF}
But this does NOT work
// DO NOT USE THIS - IT DOES NOT WORK
{$IF FMX.Types.FireMonkeyVersion < 0} // if VCL
ShowMessage ('VCL 2');
{$ELSE} // its not VCL, so it must be FMX
ShowMessage ('FMX 2');
{$ENDIF}
What if I mix and match VCL and FMX ?
Although not officially supported, it is possible for a Delphi application to use both FireMonkey and VCL units.
It is possible to embed a FireMonkey form in a VCL application and vice versa using unsupported techniques. However, I haven’t tested those scenarios with my conditional compilation code. Maybe it will work, maybe not. Ill leave it to you to look into it if you are interested. Please post a comment here if you find anything interested.
Supported Versions of Delphi
The code has been tested on XE2 to XE10.1
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About The Author
The Usual Suspect
– Scott Hollows –
- Oracle and Delphi software developer.
- Australian Delphi User Group – Western Australia Chief Cat Herder
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Hi, how to do this in C++ Builder?
There is a similar trick mentioned in Embarcadero’s own documentation:
http://docwiki.embarcadero.com/RADStudio/en/IF_directive_(Delphi)
“If the identifiers referenced in the conditional expression do not exist, the conditional expression will be evaluated as False:
{$IF NoSuchVariable > 5}
Writeln(‘This line doesn”t compile’);
{$IFEND}
You can use the FireMonkeyVersion constant (defined in FMX.Types.pas and equal to 16.1 at the XE2 Update 2 release) in an IF directive. To identify and separate FireMonkey code that is for any version higher than 16.0, surround the code with the following conditional directive:
{$IF Declared(FireMonkeyVersion) and (FireMonkeyVersion > 16.0)}
…
{$IFEND}
“
Thanks!
I found a way:
#ifdef FMX.Types.FireMonkey Version> = 0
#include
#else
#include
#endif
What about:
{$IF not declared(FireMonkeyVersion)}
DoSomethingVCL;
{$ELSE}
DoSomethingFMX;
{$IFEND}
Thanks – that works for me in VCL and FMX
I think this is the best solution so far as it is more concise and does not have the issue of “reversing the logic does not work.” that I mentioned
Im throwing in a Hello World so we have a copy / pasteable demo
{$IF not declared(FireMonkeyVersion)}
ShowMessage(‘VCL’);
{$ELSE}
ShowMessage(‘FMX’);
{$IFEND}