[compile error] MSVC 2015 does not fully support constexpr declarations

[nicolas-cadart]

Describe the error

It seems impossible to compile PCL with version >= 1.10.0 on Windows with MSVC 2015.

Apparently, Microsoft Visual Studio 2015 Update 3 does not have full support of constexpr expressions. This full support comes with MSVC 2017.

From PCL 1.10.0, some constexpr have been introduced in some basic files such as pcl/common/include/pcl/point_types.h or pcl/common/src/parse.cpp. However, these expressions are apparently not resolved at compile-time, and therefore does not exist when the compiler reaches their uses later on. This prevents compilation.

PCL 1.10.0 drops MSVC 2013 support, but not MSVC 2015. Therefore either its support should be deprecated, or fixed.

To Reproduce

After having set the dependencies from cmake-gui, I get the following errors :

C:\software\pcl\build>ninja -j1
[5/269] Building CXX object io\CMakeFiles\pcl_io.dir\src\ascii_io.cpp.obj
FAILED: io/CMakeFiles/pcl_io.dir/src/ascii_io.cpp.obj
C:\PROGRA~2\MICROS~1.0\VC\bin\X86_AM~1\cl.exe  /nologo /TP -DBOOST_LIB_DIAGNOSTIC -DPCLAPI_EXPORTS -Iinclude -IC:\software\pcl\src\common\include -IC:\software\pcl\src\octree\include -IC:\software\pcl\src\openni\include -IC:\software\pcl\src\openni2\include -IC:\software\pcl\src\ensenso\include -IC:\software\pcl\src\davidSDK\include -IC:\software\pcl\src\dssdk\include -IC:\software\pcl\src\rssdk\include -IC:\software\pcl\src\rssdk2\include -IC:\software\pcl\src\pcap\include -IC:\software\pcl\src\png\include -IC:\software\pcl\src\vtk\include -IC:\software\pcl\src\io\include -IC:\VV\build\install\include\eigen3 -IC:\software\pcl\src\recognition\include\pcl\recognition\3rdparty -IC:\VV\build\install\include\boost-1_66 /DWIN32 /D_WINDOWS /W3 /GR /EHsc /fp:precise /wd4800 /wd4521 /wd4251 /wd4275 /wd4305 /wd4355  /FS -openmp -DBOOST_ALL_DYN_LINK -DBOOST_ALL_NO_LIB /MD /O2 /Ob2 /DNDEBUG /GL   -DBOOST_ALL_NO_LIB -D_SCL_SECURE_NO_WARNINGS -D_CRT_SECURE_NO_WARNINGS -DNOMINMAX -DPCL_ONLY_CORE_POINT_TYPES  -D__SSSE3__ -D__SSE2__ -D__SSE__ /bigobj /MP12 -std:c++14 /showIncludes /Foio\CMakeFiles\pcl_io.dir\src\ascii_io.cpp.obj /Fdio\CMakeFiles\pcl_io.dir\ /FS -c C:\software\pcl\src\io\src\ascii_io.cpp
C:\software\pcl\src\common\include\pcl/pcl_macros.h(83): warning C4067: unexpected tokens following preprocessor directive - expected a newline
C:\software\pcl\src\common\include\pcl/point_types.h(810): error C3536: 'pcl::traits::has_xy_v<PointT>': cannot be used before it is initialized
C:\software\pcl\src\common\include\pcl/point_types.h(813): error C3536: 'pcl::traits::has_xy_v<PointT>': cannot be used before it is initialized
C:\software\pcl\src\common\include\pcl/point_types.h(826): error C3536: 'pcl::traits::has_xyz_v<PointT>': cannot be used before it is initialized
C:\software\pcl\src\common\include\pcl/point_types.h(829): error C3536: 'pcl::traits::has_xyz_v<PointT>': cannot be used before it is initialized
C:\software\pcl\src\common\include\pcl/point_types.h(843): error C3536: 'pcl::traits::has_normal_v<PointT>': cannot be used before it is initialized
C:\software\pcl\src\common\include\pcl/point_types.h(846): error C3536: 'pcl::traits::has_normal_v<PointT>': cannot be used before it is initialized
C:\software\pcl\src\common\include\pcl/point_types.h(857): error C3536: 'pcl::traits::has_curvature_v<PointT>': cannot be used before it is initialized
C:\software\pcl\src\common\include\pcl/point_types.h(860): error C3536: 'pcl::traits::has_curvature_v<PointT>': cannot be used before it is initialized
C:\software\pcl\src\common\include\pcl/point_types.h(871): error C3536: 'pcl::traits::has_intensity_v<PointT>': cannot be used before it is initialized
C:\software\pcl\src\common\include\pcl/point_types.h(874): error C3536: 'pcl::traits::has_intensity_v<PointT>': cannot be used before it is initialized
C:\software\pcl\src\common\include\pcl/point_types.h(886): error C3536: 'pcl::traits::has_color_v<PointT>': cannot be used before it is initialized
C:\software\pcl\src\common\include\pcl/point_types.h(889): error C3536: 'pcl::traits::has_color_v<PointT>': cannot be used before it is initialized
C:\software\pcl\src\common\include\pcl/point_types.h(900): error C3536: 'pcl::traits::has_label_v<PointT>': cannot be used before it is initialized
C:\software\pcl\src\common\include\pcl/point_types.h(903): error C3536: 'pcl::traits::has_label_v<PointT>': cannot be used before it is initialized
ninja: build stopped: subcommand failed.  

Environment :

• OS: Windows 10 with MSVC 2015 Update 3
• Compiler: Microsoft Visual Studio 14.0
• PCL Version: from v1.10.0
• PCL Type: Installed/Compiled from source
• GPU, Kinfu, CUDA enabled? No
• List and Version of dependencies used : Boost 1.66, Eigen 3.3.7, QHull master, Flann 1.9.1

Possible Solution

Easy but unclean solution is to remove these constexpr declarations and use directly the necessary values in the template declarations.

[kunaltyagi]

The min version of MSVC supported is 2017, because it brings a lot of bug fixes necessary to use C++14 dialect. Please upgrade the compiler or downgrade PCL.

[nicolas-cadart]

@kunaltyagi Thanks for clarifying that. But I think this should be clearly stated somewhere. Tutorials still use MSVC 2010, and changelog only mentions MSVC 2013 ans previous deprecations.