[Gmsh] building of gmsh on mingw64

[Christophe Geuzaine]

Hi Walter,

ENABLE_OCC_STATIC should actually not be needed anymore. Can you try the latest Git master, in which CMAKE_FIND_LIBRARY_SUFFIXES and PATH_SUFFIXES have been modified? If it doesn't work let's try to understand why and open an issue in our Gitlab about it.

Christophe


> On 22 Sep 2020, at 20:03, walter <steffe at tiscali.it> wrote:
> 
> Hello,
>  I am used to build my application (EmCAD) and gmsh on Msys2/MINGW64 platform.
> 
> Today I made a small change to the main CMakeLists.txt file of gmsh-4.6.0-source.
> This change fixes the following problem:
>  cmake/configure is not able to find the OCC libraries on Msys2/MINGW64 platform even if CASROOT is properly set.
> 
> This problem arises because:
> 1)  on Msys2/MINGW64 platform the OCC libraries are located in the following folders
> 
>     $CASROOT/${OCC_SYS_NAME}/gcc/lib  >> dll.a  libraries 
>     $CASROOT/${OCC_SYS_NAME}/gcc/bin  >> dll    libraries
> 
> 
> So I made the following small changes:
> 
> 
> line 12179 to 1273
>        if(ENABLE_OCC_STATIC)
>          set(LIBNAME lib${OCC}.a)
>        else()
>          set(LIBNAME ${OCC})
>        endif()
> 
> is replaced by:        
>        if(ENABLE_OCC_STATIC)
> 	  if(MINGW)
>             set(LIBNAME lib${OCC}.dll.a)
> 	  else()
>             set(LIBNAME lib${OCC}.a)
>          endif()
>        else()
>          set(LIBNAME ${OCC})
>        endif()
> 
> 
> line 1284 to 1285:        
>        find_library(OCC_LIB ${LIBNAME} HINTS ENV CASROOT PATH_SUFFIXES
>                     lib ${OCC_SYS_NAME}/lib ${OCC_SYS_NAME}/vc8/lib)
> 
> is replaced by:      
>        find_library(OCC_LIB ${LIBNAME} HINTS ENV CASROOT PATH_SUFFIXES lib bin
>                     lib ${OCC_SYS_NAME} ${OCC_SYS_NAME}/vc8 ${OCC_SYS_NAME}/gcc )
> 
> 
> line 1306 to 1307:  
>        find_library(OCC_CAF_LIB ${OCC} HINTS ENV CASROOT PATH_SUFFIXES
>                    lib ${OCC_SYS_NAME}/lib ${OCC_SYS_NAME}/vc8/lib)
> 
> is replaced by:
>        find_library(OCC_CAF_LIB ${OCC} HINTS ENV CASROOT PATH_SUFFIXES lib bin
>                    lib ${OCC_SYS_NAME} ${OCC_SYS_NAME}/vc8 ${OCC_SYS_NAME}/gcc)
> 
> 
> -bin has been added to PATH_SUFFIXES in both calls to find_library.
> -${OCC_SYS_NAME}/gcc subfolder explitely added to ${OCC_SYS_NAME}/vc8
> -lib was removed from some explicit subfolders because it is already appended by PATH_SUFFIXES
> 
> With this change, when the option ENABLE_OCC_STATIC is activated on a Msys2/MINGW64 platform, gmsh is linked with libTKernel.dll.a ...
> 
> libTKernel.dll.a is an import library in the microsoft world. 
> I think that this kind of library is meant to import the libTKernel.dll library placed in the gcc/bin folder.
> I do not know if it make any difference with direct linkage to the dll.
> 
> 
> Walter
> 
> 
> 
> 
> 
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— 
Prof. Christophe Geuzaine
University of Liege, Electrical Engineering and Computer Science 
http://www.montefiore.ulg.ac.be/~geuzaine