Issue with <complex.h> use om Windows - with MSVC

[willend]

Status update Nov 23rd:

Common mccode:

• Wrapper header mccode-complex-lib is in place and used in a few comps.

McStas done:

• all McStas comps originally using <complex.h> and related instruments now fixed and run on Windows.
• Status McStas (nightly run output)

McXtrace done:

• Status McXtrace (nightly run output)
  Contrib fixed:

mcxtrace-comps/contrib/Mirror_toroid_pothole.comp
mcxtrace-comps/contrib/SANSPDB*.comp

Sources fixed:

mcxtrace-comps/sources/Source_genesis13.comp
mcxtrace-comps/sources/Source_simplex.comp

Monitors fixed:
mcxtrace-comps/monitors/PSD_monitor_coh.comp

( Obsolete fixed: mcxtrace-comps/obsolete/Perfect_crystal.comp )

Instruments fixed: (required?)
mcxtrace-comps/examples/MAXIV/MAXIV_Bloch/MAXIV_Bloch.instr

McXtrace work missing:

Optics:

mcxtrace-comps/optics/Multilayer_elliptic.comp:
mcxtrace-comps/optics/Mirror_elliptic.comp
mcxtrace-comps/optics/Mirror_curved.comp
mcxtrace-comps/optics/Grating_reflect.comp
mcxtrace-comps/optics/Capillary.comp

Contrib:

mcxtrace-comps/contrib/Bragg_crystal_BC.comp
mcxtrace-comps/contrib/Bragg_crystal_bent_BC.comp

libs:

mcxtrace-comps/share/reflectivity-lib.h and c
mcxtrace-comps/share/perfect_crystals-lib.h and c

[willend]

Annoying...

https://learn.microsoft.com/en-us/cpp/c-runtime-library/complex-math-support?view=msvc-170

No internal support for types like e.g. double complex, apparently needs:

• mapping to internal struct type _Dcomplex
• ... PLUS define functions for arithmetics, as mentioned in e.g.

https://stackoverflow.com/questions/1063406/c99-complex-support-with-visual-studio

[willend]

Workaround for those in dire need:

1. Install gcc with dependencies on the Windows box: micromamba install m2-msys2-runtime m2w64-gcc m2w64-gsl
2. Fix the standard CFLAGS to be 'gcc' style, i.e. "CFLAGS": "-IC:/Users/peterwillendrup/AppData/Roaming/mamba/envs/mcstas/Library/include -LC:/Users/peterwillendrup/AppData/Roaming/mamba/envs/mcstas/Library/lib -DNDEBUG -D_POSIX_SOURCE -lm"

[willend]

Some inspiration may be taken from a snippet of code we include from SasView/sasmodels:
https://github.com/mccode-dev/McCode/blob/main/mcstas-comps/sasmodels-generator/models/lib/cl_complex.h

[willend]

To fully resolve use of <complex.h> for McStas on Windows with MSVC, the following comps should be corrected (and corresponding text instruments added):

mcstas-comps/contrib/SANSPDBFast.comp:	#include <complex.h>
mcstas-comps/contrib/SANSPDB.comp:	#include <complex.h>

For McXtrace much more work remains across comps, instrs and libs:

mcxtrace-comps/monitors/PSD_monitor_coh.comp:#include <complex.h>
mcxtrace-comps/obsolete/Perfect_crystal.comp:#include <complex.h>
mcxtrace-comps/contrib/Mirror_toroid_pothole.comp: #include <complex.h>
mcxtrace-comps/contrib/SAXSPDBFast.comp:	#include <complex.h>
mcxtrace-comps/examples/MAXIV/MAXIV_Bloch/MAXIV_Bloch.instr:#include <complex.h>
mcxtrace-comps/sources/Source_genesis13.comp:#include <complex.h>
mcxtrace-comps/sources/Source_simplex.comp: #include <complex.h>
mcxtrace-comps/optics/Multilayer_elliptic.comp:#include <complex.h>
mcxtrace-comps/optics/Mirror_elliptic.comp: #include <complex.h>
mcxtrace-comps/optics/Mirror_curved.comp:#include <complex.h>
mcxtrace-comps/optics/Grating_reflect.comp: #include <complex.h>
mcxtrace-comps/optics/Capillary.comp:#include <complex.h>
mcxtrace-comps/share/reflectivity-lib.h:#include <complex.h>
mcxtrace-comps/share/perfect_crystals-lib.h:#include <complex.h>
mcxtrace-comps/share/reflectivity-lib.c:#include <complex.h>
mcxtrace-comps/share/reflectivity-lib.c:#include <complex.h>

[ebknudsen]

For McXtrace also

mcxtrace-comps/contrib/Bragg_crystal_BC.comp
mcxtrace-comps/contrib/Bragg_crystal_bent_BC.comp

and

mcxtrace-comps/share/perfect_crystals-lib.c
mcxtrace-comps/share/perfect_crystals-lib.h

(the last one you already had in the list, but they are connected

The latter is likely a biggish job, so perhaps warrants its own issue. @willend Feel free to make one and assign me if you think it appropriate.