FreeCAD fail to build with OCE (community eddition)

[cbalint]

* As per description: https://www.freecadweb.org/tracker/view.php?id=4190

This [PR#2680](https://github.com/FreeCAD/FreeCAD/pull/2680) introduced a header file [Standard_Handle.hxx](https://github.com/FreeCAD/FreeCAD/blob ... lper.h#L26) not available in OCE community edition.

Unsure if it is intentional, is FreeCAD dropping OCE support.

Error is obvious:
```
[ 35%] Building CXX object src/Mod/TechDraw/App/CMakeFiles/TechDraw.dir/AppTechDrawPy.cpp.o
In file included from /home/cbalint/rpmbuild/BUILD/FreeCAD/src/Mod/TechDraw/App/AppTechDrawPy.cpp:73:
/home/cbalint/rpmbuild/BUILD/FreeCAD/src/Mod/TechDraw/App/DrawDimHelper.h:26:10: fatal error: Standard_Handle.hxx: No such file or directory
26 | #include <Standard_Handle.hxx>
```

[wmayer]

Unsure if it is intentional, is FreeCAD dropping OCE support.

As far as I can see that's the one and only location in the FreeCAD code base that includes this header. As OCE/OCC internally includes the appropriate header file to offer the Handle() class it's superfluous to explicitly include it in FreeCAD code, too.

So, in this case it's trivial to fix the build for OCE but in the long-term OCE support might be dropped since the major Linux distributions switch back to OCC.

[vocx]

...
Unsure if it is intentional, is FreeCAD dropping OCE support.
...

I haven't seen an official announcement, however, OCE, the community edition, has been pretty much ignored by FreeCAD since 2017 or so.

See

• [Ubuntu Daily PPA] Transitioning to OCCT7, VTK7...
• Ubuntu Daily Builds PPA now using OCC 7.1.0

I don't think anybody of the major developers tests their code against OCE, only the official OCCT 7.x series.

That FreeCAD still compiled against OCE was incidental; I don't think anybody explicitly wanted to retain "support" for it. It seems to me OCE is de facto obsolete, even if there was no official announcement.

[sukoi26]

Hello,
i suggest to change the line code
#include <Standard_Handle.hxx>
by
# include <Geom2d_Curve.hxx>

it work on OCE result info :

OS: Debian GNU/Linux bullseye/sid (GNOME/gnome)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.18702 (Git)
Build type: Unknown
Branch: master
Hash: aab61f3e151e65975e370b4d8ff3611d6355730c
Python version: 3.7.5
Qt version: 5.12.5
Coin version: 4.0.0a
OCC version: 6.9.1.oce-0.18
....

[sukoi26]

test wih OCC

OS: Debian GNU/Linux bullseye/sid (GNOME/gnome)
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.19.18702 (Git)
Build type: Unknown
Branch: master
Hash: aab61f3e151e65975e370b4d8ff3611d6355730c
Python version: 3.7.5
Qt version: 5.12.5
Coin version: 4.0.0a
OCC version: 7.3.0

[wmayer]

git commit ac4e23012a4b6

[wandererfan]

git commit ac4e23012a4b6

Woke up this morning and this was already fixed! Thank you.

[cbalint]

Thank you Folks !

[sukoi26]

thank a lot wmayer for the commit