gmsh[occ] feature doesn't actually enable OpenCASCADE support

[l1308752310]

Description

I installed gmsh with the occ feature to enable OpenCASCADE support, but after installation, the generated gmshConfig.h shows that OCC is not actually enabled.

Environment

• OS: Windows 11

• Compiler: MSVC 2022 (v143)

• vcpkg version: vcpkg package management program version 2025-10-16-71538f2694db93da4668782d094768ba74c45991

• Triplet: x64-windows

Steps to Reproduce

vcpkg install gmsh[occ]:x64-windows

The installation completes successfully, and opencascade is installed as a dependency:

PS D:\vcpkg\vcpkg> vcpkg list gmsh
gmsh:x64-windows                                  4.14.0              Gmsh is an open source 3D finite element mesh ge...
gmsh[occ]:x64-windows                                                 Enable OpenCASCADE modules

Expected Behavior

In the installed gmshConfig.h, I expected to see:

#define HAVE_OCC

Actual Behavior

Instead, the file shows:

// Gmsh - Copyright (C) 1997-2025 C. Geuzaine, J.-F. Remacle
//
// See the LICENSE.txt file in the Gmsh root directory for license information.
// Please report all issues on https://gitlab.onelab.info/gmsh/gmsh/issues.

#ifndef GMSH_CONFIG_H
#define GMSH_CONFIG_H

/* #undef HAVE_3M */
#define HAVE_64BIT_SIZE_T
/* #undef HAVE_ACIS */
/* #undef HAVE_ALGLIB */
/* #undef HAVE_ANN */
/* #undef HAVE_BAMG */
/* #undef HAVE_BLAS */
/* #undef HAVE_BLOSSOM */
/* #undef HAVE_CAIRO */
/* #undef HAVE_DLOPEN */
/* #undef HAVE_DINTEGRATION */
/* #undef HAVE_DOMHEX */
/* #undef HAVE_EIGEN */
/* #undef HAVE_FLTK */
/* #undef HAVE_GEOMETRYCENTRAL */
/* #undef HAVE_GMM */
/* #undef HAVE_GMP */
/* #undef HAVE_HXT */
/* #undef HAVE_KBIPACK */
/* #undef HAVE_LAPACK */
/* #undef HAVE_LIBCGNS */
/* #undef HAVE_LIBCGNS_CPEX0045 */
/* #undef HAVE_LIBJPEG */
/* #undef HAVE_LIBPNG */
/* #undef HAVE_LIBZ */
/* #undef HAVE_LINUX_JOYSTICK */
/* #undef HAVE_MATHEX */
/* #undef HAVE_MED */
#define HAVE_MESH
/* #undef HAVE_MESQUITE */
/* #undef HAVE_METIS */
/* #undef HAVE_MMG */
/* #undef HAVE_MPEG_ENCODE */
/* #undef HAVE_MPI */
/* #undef HAVE_MUMPS */
/* #undef HAVE_NETGEN */
#define HAVE_NII2MESH
/* #undef HAVE_NUMPY */
/* #undef HAVE_NO_INTPTR_T */
#define HAVE_NO_SOCKLEN_T
/* #undef HAVE_NO_STDINT_H */
/* #undef HAVE_NO_VSNPRINTF */
/* #undef HAVE_OCC */
/* #undef HAVE_OCC_CAF */
/* #undef HAVE_ONELAB */
/* #undef HAVE_ONELAB2 */
/* #undef HAVE_ONELAB_METAMODEL */
/* #undef HAVE_UDT */
/* #undef HAVE_OPENGL */
/* #undef HAVE_OPTHOM */
/* #undef HAVE_OSMESA */
/* #undef HAVE_P4EST */
/* #undef HAVE_PARASOLID */
/* #undef HAVE_PARASOLID_STEP */
#define HAVE_PARSER
/* #undef HAVE_PETSC */
/* #undef HAVE_PETSC4PY */
/* #undef HAVE_PLUGINS */
#define HAVE_POST
/* #undef HAVE_POPPLER */
/* #undef HAVE_QUADTRI */
/* #undef HAVE_QUADMESHINGTOOLS */
/* #undef HAVE_REVOROPT */
/* #undef HAVE_SALOME */
/* #undef HAVE_SGEOM */
/* #undef HAVE_SLEPC */
/* #undef HAVE_SOLVER */
#define HAVE_UNTANGLE
/* #undef HAVE_TAUCS */
#define HAVE_TETGENBR
#define HAVE_TINYXML2
/* #undef HAVE_TOUCHBAR */
/* #undef HAVE_VISUDEV */
/* #undef HAVE_VOROPP */
/* #undef HAVE_WINSLOWUNTANGLER */
/* #undef HAVE_ZIPPER */

#define GMSH_CONFIG_OPTIONS " 64Bit Mesh Nii2mesh NoSocklenT Parser Post TetGen/BR TinyXML2 Untangle tinyobjloader"

#pragma warning(disable:4800 4244 4267)

#endif

Investigation

I checked the port files:

ports/gmsh/vcpkg.json:

{
  "name": "gmsh",
  "version": "4.14.0",
  "description": "Gmsh is an open source 3D finite element mesh generator with a built-in CAD engine and post-processor.",
  "homepage": "https://gmsh.info",
  "license": "LGPL-2.0-or-later",
  "supports": "!uwp",
  "dependencies": [
    "blas",
    {
      "name": "vcpkg-cmake",
      "host": true
    },
    {
      "name": "vcpkg-cmake-config",
      "host": true
    }
  ],
  "features": {
    "graphics": {
      "description": "Enable building graphics lib even without GUI (advanced)",
      "dependencies": [
        "libjpeg-turbo",
        "libpng",
        "opengl",
        "zlib"
      ]
    },
    "mpi": {
      "description": "Enable MPI (experimental, not used for meshing)",
      "dependencies": [
        "openmpi"
      ]
    },
    "occ": {
      "description": "Enable OpenCASCADE modules",
      "dependencies": [
        "caf",
        "freetype",
        "opencascade",
        "tbb"
      ]
    },
    "zipper": {
      "description": "Enable Zip file compression/decompression",
      "dependencies": [
        "zlib"
      ]
    }
  }
}

Build Logs

From buildtrees/gmsh/config-x64-windows-rel-out.log:

-- The CXX compiler identification is MSVC 19.44.35219.0
-- The C compiler identification is MSVC 19.44.35219.0
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Check for working CXX compiler: D:/Program Files/Microsoft Visual Studio/2022/Professional/VC/Tools/MSVC/14.44.35207/bin/Hostx64/x64/cl.exe - skipped
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Check for working C compiler: D:/Program Files/Microsoft Visual Studio/2022/Professional/VC/Tools/MSVC/14.44.35207/bin/Hostx64/x64/cl.exe - skipped
-- Detecting C compile features
-- Detecting C compile features - done
-- Looking for sys/types.h
-- Looking for sys/types.h - found
-- Looking for stdint.h
-- Looking for stdint.h - found
-- Looking for stddef.h
-- Looking for stddef.h - found
-- Check size of size_t
-- Check size of size_t - done
-- Found 64Bit
-- Found Mesh
-- Found Post
-- Found Parser
-- Found tinyobjloader
-- Found TinyXML2
-- Found TetGen/BR
-- Found Nii2mesh
-- Found Untangle
-- Looking for vsnprintf
-- Looking for vsnprintf - found
-- Looking for sys/socket.h
-- Looking for sys/socket.h - not found
-- Check size of socklen_t
-- Check size of socklen_t - failed
-- Found NoSocklenT
-- Check size of intptr_t
-- Check size of intptr_t - done
-- Looking for dlfcn.h
-- Looking for dlfcn.h - not found
-- Performing Test WALL
-- Performing Test WALL - Success
-- Performing Test NOWARN
-- Performing Test NOWARN - Success
-- Performing Test NOOPT
-- Performing Test NOOPT - Failed
-- 
-- Gmsh 4.14.0 has been configured for Windows64
-- 
--  * Build options: 64Bit Mesh Nii2mesh NoSocklenT Parser Post TetGen/BR TinyXML2 Untangle tinyobjloader
--  * Build type: Release
--  * C compiler: D:/Program Files/Microsoft Visual Studio/2022/Professional/VC/Tools/MSVC/14.44.35207/bin/Hostx64/x64/cl.exe
--  * C++ compiler: D:/Program Files/Microsoft Visual Studio/2022/Professional/VC/Tools/MSVC/14.44.35207/bin/Hostx64/x64/cl.exe
--  * Install prefix: D:/vcpkg/vcpkg/packages/gmsh_x64-windows
-- 
-- Configuring done (12.8s)
-- Generating done (0.2s)
-- Build files have been written to: D:/vcpkg/vcpkg/buildtrees/gmsh/x64-windows-rel

Question

Is this a known issue, or am I missing something in how to properly enable the OCC feature?

If this is indeed a bug, I'm happy to help create a fix. It seems like the portfile.cmake needs to be updated to:

1. Check if the occ feature is enabled
2. Pass the appropriate CMake option (-DENABLE_OCC=ON)
3. Ensure OpenCASCADE headers/libraries are properly linked

[dg0yt]

Bug. #48658.