Predefined symbol to select between Lazarus and Delphi

Question

I am looking for a predefined symbol to write a code like that:

{$IFDEF LAZARUS}
// code compiles by fpc/lazarus
{$ELSE}
// code compiles by delphi
{$ENDIF}

Womenfolk

Answer 1

Use FPC             

{$IFDEF FPC}

Cupellation

FPC is defined by the compiler rather than the IDE. So it will be correct for all IDEs that use FPC as their compiler. – Cupellation

Yes I don't think there's a directive to detect the IDE at all. After all, the IDE is just an enriched Notepad to type your code in. – Cubeb

IDE itself could possibly define a conditional symbol, and store it in compiler options. – Womenfolk

What does it matter which IDE is invoking the compiler? – Cupellation

Maybe he thinks IDE = widgets library, hence Lazarus = LCL. – Concomitance

I also think the code should check for both FPC and Delphi. There is GNU Pascal, there is Virtual Pascal, OpenSibil, MIDlet Pascal and who knows what else, even Oxygene is compatible to some point. I am certain that both FPC and DELPHI should be checked. Maybe they should be checked once in the header, and if none defined then abort compilation due to non-supported compiler. But at lease once Delphi presence should be ensured – Concomitance

I am porting a unit test project to Lazarus and need ex to use different unit names in uses clause. DUnit implementation is specific to IDE. – Womenfolk

I am currently experimenting with built-in Lazarus GUI testrunner – Womenfolk

@Arioch: starting in XE2 (or maybe XE, I forget which), the Delphi compiler started defining the DCC conditional for itself. Prior to that, there was no defining conditional to identify the Delphi compiler, except indirectly via the version-specific VERxxx conditionals. – Chandelle

@GolezTrol: not so simple as in Delphi you may have some code related to the IDE itself, ie: when you use ToolsAPI. – Nominal

@Nominal That is still compiled using the Delphi compiler (for the Delphi IDE) or by FreePascal if you compile (for) Lazarus. – Cubeb

Maybe in combination with a define for designtime parts of components – Alanson

Answer 2

For GUI applications afaik the "LCL" symbol is defined inside Lazarus projects. In this case it probably won't matter.

In general, for bigger codebases, I would avoid having too much ifdef FPC/LCL and ifdef in your sourcecode though. It makes adding an exception or other version harder.

Use a system like JCL and Zeos(7) are using, where you give most differences an own name (like "USE_FPCUNIT" or "USE_DUNIT") and link these to versions in a central includefile.

For a short treatise on the subject see http://www.stack.nl/~marcov/porting.pdf (chapter 2)

P.s. I would consider Pocketstudio, TP,GPC,VP and WDSybil (and whatever I forgot) dead for most practical purposes and the bytecode variants Canterbury Pascal/Component Pascal/Oxygene/Prism/Delphi.NET incompatible (most are more Oberon than Pascal anyway). That pretty much leaves Delphi, Kylix and FPC to worry about.

Alanson