XML parsing with non-standard linux-locale

[benjaminhuth]

I'm not sure if this is really a bug, but certainly a unexpected behavior at least for me:

I tried to parse a DD4hep XML-file (this one specifically, though it shouldn't matter for the issue: https://gitlab.cern.ch/acts/OpenDataDetector/-/blob/main/xml/OpenDataDetector.xml) with the ACTS DD4hep interface, and got the following error:.

RuntimeError: dd4hep: Evaluator::Object : syntax error : value=10.0*m [Evaluation error]

After quite some time of debugging I found the error in the configured locale, where the LC_NUMERIC entry was set to de_DE.UTF-8, which caused the failure of the floating point parsing (it expected a comma). Changing this value to the default C-locale resolved the error.

From my perspective the dependence on the configured locale for the parsing causes hard to debug errors and should be fixed (or at least checked with a warning).

• OS version: e.g. Fedora 5.17.6-200.fc35.x86_64
• Compiler version: GCC 11.3.1
• DD4hep version: v01-17

[MarkusFrankATcernch]

After quite some investigations:
Cannot be fixed if the old locales in C and C++ should be restored.