[fpc-pascal] Debug and Release RTL & FCL side by side

Michael Van Canneyt michael at freepascal.org
Fri Apr 29 11:34:27 CEST 2016

On Fri, 29 Apr 2016, Graeme Geldenhuys wrote:

> Hi,
> I sometimes hit a bug in my applications, but then there is no Stack
> Trace information, or simply something like 3 entries that don't give
> much information. See attached screenshot as an example. Apparently this
> is caused by the fact that I'm using a Release build of the RTL and FCL
> and the error was raised inside the RTL or FCL code.
> So is there a recommended FPC setup having a Release and Debug RTL & FCL
> side by side. Then in my IDE of choice (or build scripts) I can switch
> between them as needed. I believe Delphi had a similar setup (or maybe
> it was only for the VCL), but its been too long since I really used
> Delphi to remember what Borland did.

There is none.

what you can do is create install debug versions of the RTL/package units under


and then compile your program using -dDEBUGRTL, with in your .fpc.cfg


The compiler will then pick the debug versions of the RTL units.


More information about the fpc-pascal mailing list