Fix Windows build compatibility (MSVC cl.exe and clang-cl)

.gitignore

@@ -1,3 +1,4 @@
 build
 .vscode
 *.*.swp
+build*/

CMakeLists.txt

@@ -3,6 +3,18 @@ include(FetchContent)
 
 # Set up project definition + version information
 project( ExchCXX VERSION 1.0.0 LANGUAGES C CXX )
+set(CMAKE_CXX_STANDARD 17)
+set(CMAKE_CXX_STANDARD_REQUIRED ON)
+
+if(MSVC)
+  # /EHsc: standard C++ exception-handling model (required by STL and noexcept).
+  # /permissive-: conformance mode — recognises C++ alternative tokens (not, and, or, …).
+  # Scoped to CXX only so libxc's C sources are not affected.
+  add_compile_options(
+    $<$<COMPILE_LANGUAGE:CXX>:/EHsc>
+    $<$<COMPILE_LANGUAGE:CXX>:/permissive->
+  )
+endif()
 
 # ExchCXX Options
 option( EXCHCXX_ENABLE_BENCHMARK "Enable Performance Benchmark" OFF )
@@ -81,7 +93,7 @@ else()
     # if pinning to specific SHA change the FETCHCONTENT_LIBXC_GIT_SHALLOW default to OFF, https://cmake.org/cmake/help/latest/module/ExternalProject.html#git
     GIT_TAG 7.0.0
     GIT_SHALLOW ${FETCHCONTENT_LIBXC_GIT_SHALLOW}
-    PATCH_COMMAND sed -i -e "s/p->info->family != XC_KINETIC/p->info->kind != XC_KINETIC/g" src/work_mgga_inc.c
+    PATCH_COMMAND "${CMAKE_COMMAND}" -P "${CMAKE_CURRENT_LIST_DIR}/cmake/patch_libxc_work_mgga.cmake"
   )
   set( Libxc_VERSION 7.0.0 )
 
@@ -90,12 +102,16 @@ else()
 
   FetchContent_MakeAvailable( libxc )
   add_library( Libxc::xc ALIAS xc )
-  target_include_directories( xc 
-    PUBLIC 
+  target_include_directories( xc
+    PUBLIC
       $<BUILD_INTERFACE:${libxc_SOURCE_DIR}/src>
       $<BUILD_INTERFACE:${libxc_BINARY_DIR}/src>
       $<BUILD_INTERFACE:${libxc_BINARY_DIR}>
   )
+  if(MSVC)
+    # Suppress CRT deprecation warnings (strcpy, sscanf, etc.) in libxc C sources
+    target_compile_definitions( xc PRIVATE _CRT_SECURE_NO_WARNINGS )
+  endif()
   message( STATUS "Libxc Source: ${libxc_SOURCE_DIR}" )
 
   # disable unity builds for libxc

cmake/patch_libxc_work_mgga.cmake

@@ -0,0 +1,13 @@
+# patch_libxc_work_mgga.cmake
+# Portable replacement for:
+#   sed -i -e "s/p->info->family != XC_KINETIC/p->info->kind != XC_KINETIC/g" src/work_mgga_inc.c
+# Run from the libxc source directory via PATCH_COMMAND.
+
+set(_file "src/work_mgga_inc.c")
+if(NOT EXISTS "${_file}")
+  message(FATAL_ERROR "patch_libxc_work_mgga.cmake: ${_file} not found (cwd=${CMAKE_CURRENT_SOURCE_DIR})")
+endif()
+
+file(READ "${_file}" _content)
+string(REPLACE "p->info->family != XC_KINETIC" "p->info->kind != XC_KINETIC" _content "${_content}")
+file(WRITE "${_file}" "${_content}")

include/exchcxx/exceptions/exchcxx_exception.hpp

@@ -47,7 +47,6 @@
 
 #include <stdexcept>
 #include <string>
-#include <string.h>
 #include <sstream>
 
 namespace ExchCXX {
@@ -57,27 +56,27 @@ class exchcxx_exception : public std::exception {
   std::string file_;
   int         line_;
   std::string msg_prefix_;
+  std::string what_msg_;
 
   const char* what() const noexcept override {
-     std::stringstream ss;
-     ss << "EXCHCXX Exception (" << msg_prefix_ << ")" << std::endl
-        << "  File       " << file_ << std::endl
-        << "  Line       " << line_ << std::endl;
-
-     auto msg = ss.str();
-
-     return strdup( msg.c_str() );
+    return what_msg_.c_str();
   }
 
 public:
 
   exchcxx_exception( std::string file, int line, std::string msg) :
-    file_(file), line_(line), msg_prefix_(msg) { }
+    file_(std::move(file)), line_(line), msg_prefix_(std::move(msg)) {
+    std::stringstream ss;
+    ss << "EXCHCXX Exception (" << msg_prefix_ << ")" << std::endl
+       << "  File       " << file_ << std::endl
+       << "  Line       " << line_ << std::endl;
+    what_msg_ = ss.str();
+  }
 
 };
 
 #define EXCHCXX_BOOL_CHECK( MSG, V ) \
-  if( not (V) ) \
+  if( !(V) ) \
     throw exchcxx_exception( __FILE__, __LINE__, MSG );
 
 }

include/exchcxx/impl/builtin/kernels/deorbitalized.hpp

@@ -70,10 +70,9 @@ struct kernel_traits<Deorbitalized<XCEF,KEDF>> {
   static constexpr bool needs_laplacian = true;
   static constexpr bool is_kedf = false;
   static constexpr bool is_epc  = false;
-  static constexpr double exx_coeff = xc_traits::exx_coeff + ke_traits::exx_coeff;
 
   BUILTIN_KERNEL_EVAL_RETURN
-    eval_exc_unpolar( double rho, double sigma, double lapl, double tau, double& eps ) {
+    eval_exc_unpolar( double rho, double sigma, double lapl, [[maybe_unused]] double tau, double& eps ) {
 
     double TAU;
     ke_traits::eval_exc_unpolar(rho, sigma, lapl, 0.0, TAU);
@@ -84,7 +83,7 @@ struct kernel_traits<Deorbitalized<XCEF,KEDF>> {
   }
 
   BUILTIN_KERNEL_EVAL_RETURN
-    eval_exc_vxc_unpolar( double rho, double sigma, double lapl, double tau, double& eps, double& vrho, double& vsigma, double& vlapl, double& vtau ) {
+    eval_exc_vxc_unpolar( double rho, double sigma, double lapl, [[maybe_unused]] double tau, double& eps, double& vrho, double& vsigma, double& vlapl, double& vtau ) {
 
     double TAU, vrho_k, vsigma_k, vlapl_k, dummy;
     ke_traits::eval_exc_vxc_unpolar(rho, sigma, lapl, 0.0, TAU, vrho_k, vsigma_k, vlapl_k, dummy);
@@ -101,7 +100,7 @@ struct kernel_traits<Deorbitalized<XCEF,KEDF>> {
   }
 
   BUILTIN_KERNEL_EVAL_RETURN
-    eval_exc_polar( double rho_a, double rho_b, double sigma_aa, double sigma_ab, double sigma_bb, double lapl_a, double lapl_b, double tau_a, double tau_b, double& eps ) {
+    eval_exc_polar( double rho_a, double rho_b, double sigma_aa, double sigma_ab, double sigma_bb, double lapl_a, double lapl_b, [[maybe_unused]] double tau_a, [[maybe_unused]] double tau_b, double& eps ) {
 
     double TAU_A, TAU_B;
     ke_traits::eval_exc_polar(rho_a, 0.0, sigma_aa, 0.0, 0.0, lapl_a, 0.0, 0.0, 0.0, TAU_A);
@@ -114,9 +113,9 @@ struct kernel_traits<Deorbitalized<XCEF,KEDF>> {
   }
 
   BUILTIN_KERNEL_EVAL_RETURN
-    eval_exc_vxc_polar( double rho_a, double rho_b, double sigma_aa, double sigma_ab, double sigma_bb, double lapl_a, double lapl_b, double tau_a, double tau_b, double& eps, double& vrho_a, double& vrho_b, double& vsigma_aa, double& vsigma_ab, double& vsigma_bb, double& vlapl_a, double& vlapl_b, double& vtau_a, double& vtau_b ) {
+    eval_exc_vxc_polar( double rho_a, double rho_b, double sigma_aa, double sigma_ab, double sigma_bb, double lapl_a, double lapl_b, [[maybe_unused]] double tau_a, [[maybe_unused]] double tau_b, double& eps, double& vrho_a, double& vrho_b, double& vsigma_aa, double& vsigma_ab, double& vsigma_bb, double& vlapl_a, double& vlapl_b, double& vtau_a, double& vtau_b ) {
 
-    double TAU_A, TAU_B, vrho_a_k, vrho_b_k, vsigma_aa_k, vsigma_bb_k, vlapl_a_k, vlapl_b_k, vtau_k, dummy;
+    double TAU_A, TAU_B, vrho_a_k, vrho_b_k, vsigma_aa_k, vsigma_bb_k, vlapl_a_k, vlapl_b_k, dummy;
     ke_traits::eval_exc_vxc_polar(rho_a, 0.0, sigma_aa, 0.0, 0.0, lapl_a, 0.0, 0.0, 0.0, TAU_A, vrho_a_k, dummy, vsigma_aa_k, dummy, dummy, vlapl_a_k, dummy, dummy, dummy);
     ke_traits::eval_exc_vxc_polar(rho_b, 0.0, sigma_bb, 0.0, 0.0, lapl_b, 0.0, 0.0, 0.0, TAU_B, vrho_b_k, dummy, vsigma_bb_k, dummy, dummy, vlapl_b_k, dummy, dummy, dummy);
 

include/exchcxx/impl/builtin/kernels/screening_interface.hpp

@@ -394,7 +394,7 @@ struct mgga_screening_interface {
       constexpr auto sigma_tol_sq = traits::sigma_tol * traits::sigma_tol;
       sigma = safe_max(sigma, sigma_tol_sq); 
       tau   = safe_max(tau, traits::tau_tol);
-      if constexpr (not traits::is_kedf) {
+      if constexpr (!traits::is_kedf) {
         sigma = enforce_fermi_hole_curvature(sigma, rho, tau);
       }
 
@@ -421,7 +421,7 @@ struct mgga_screening_interface {
       sigma_bb = safe_max(sigma_bb, sigma_tol_sq); 
       tau_a = safe_max(tau_a, traits::tau_tol);
       tau_b = safe_max(tau_b, traits::tau_tol);
-      if constexpr (not traits::is_kedf) {
+      if constexpr (!traits::is_kedf) {
         sigma_aa = enforce_fermi_hole_curvature(sigma_aa, rho_a, tau_a);
         sigma_bb = enforce_fermi_hole_curvature(sigma_bb, rho_b, tau_b);
       }
@@ -450,7 +450,7 @@ struct mgga_screening_interface {
       constexpr auto sigma_tol_sq = traits::sigma_tol * traits::sigma_tol;
       sigma = safe_max(sigma, sigma_tol_sq); 
       tau   = safe_max(tau, traits::tau_tol);
-      if constexpr (not traits::is_kedf) {
+      if constexpr (!traits::is_kedf) {
         sigma = enforce_fermi_hole_curvature(sigma, rho, tau);
       }
       traits::eval_exc_vxc_unpolar_impl(rho, sigma, lapl, tau, 
@@ -489,7 +489,7 @@ struct mgga_screening_interface {
       sigma_bb = safe_max(sigma_bb, sigma_tol_sq); 
       tau_a = safe_max(tau_a, traits::tau_tol);
       tau_b = safe_max(tau_b, traits::tau_tol);
-      if constexpr (not traits::is_kedf) {
+      if constexpr (!traits::is_kedf) {
         sigma_aa = enforce_fermi_hole_curvature(sigma_aa, rho_a, tau_a);
         sigma_bb = enforce_fermi_hole_curvature(sigma_bb, rho_b, tau_b);
       }
@@ -519,7 +519,7 @@ BUILTIN_KERNEL_EVAL_RETURN
       constexpr auto sigma_tol_sq = traits::sigma_tol * traits::sigma_tol;
       sigma = safe_max(sigma, sigma_tol_sq); 
       tau   = safe_max(tau, traits::tau_tol);
-      if constexpr (not traits::is_kedf) {
+      if constexpr (!traits::is_kedf) {
         sigma = enforce_fermi_hole_curvature(sigma, rho, tau);
       }
       traits::eval_fxc_unpolar_impl(rho, sigma, lapl, tau, 
@@ -575,7 +575,7 @@ BUILTIN_KERNEL_EVAL_RETURN
       sigma_bb = safe_max(sigma_bb, sigma_tol_sq); 
       tau_a = safe_max(tau_a, traits::tau_tol);
       tau_b = safe_max(tau_b, traits::tau_tol);
-      if constexpr (not traits::is_kedf) {
+      if constexpr (!traits::is_kedf) {
         sigma_aa = enforce_fermi_hole_curvature(sigma_aa, rho_a, tau_a);
         sigma_bb = enforce_fermi_hole_curvature(sigma_bb, rho_b, tau_b);
       }
@@ -621,7 +621,7 @@ BUILTIN_KERNEL_EVAL_RETURN
       sigma = safe_max(sigma, sigma_tol_sq); 
       tau = safe_max(tau, traits::tau_tol);
 
-      if constexpr (not traits::is_kedf) {
+      if constexpr (!traits::is_kedf) {
         sigma = enforce_fermi_hole_curvature(sigma, rho, tau);
       }
 
@@ -686,7 +686,7 @@ BUILTIN_KERNEL_EVAL_RETURN
       tau_a = safe_max(tau_a, traits::tau_tol);
       tau_b = safe_max(tau_b, traits::tau_tol);
 
-      if constexpr (not traits::is_kedf) {
+      if constexpr (!traits::is_kedf) {
         sigma_aa = enforce_fermi_hole_curvature(sigma_aa, rho_a, tau_a);
         sigma_bb = enforce_fermi_hole_curvature(sigma_bb, rho_b, tau_b);
       }

include/exchcxx/xc_functional.hpp

@@ -92,7 +92,7 @@ class XCFunctional {
   inline bool sanity_check() const {
 
     // Must have one kernel
-    if( not kernels_.size() ) return false;
+    if( !kernels_.size() ) return false;
 
     // Polarization is all or nothing
     int polar_one = kernels_.at(0).second.is_polarized();
@@ -103,7 +103,7 @@ class XCFunctional {
       }
     ); 
 
-    if( not polar_all ) return false;
+    if( !polar_all ) return false;
 
     // If we made it, kernel is sane
     return true;
@@ -164,7 +164,7 @@ class XCFunctional {
     return std::any_of( 
       kernels_.begin(), kernels_.end(),
       [](const auto& x) { return x.second.is_gga(); }
-    ) and not is_mgga();
+    ) && !is_mgga();
   }
 
   inline bool is_mgga() const {

src/CMakeLists.txt

@@ -16,6 +16,33 @@ add_library( exchcxx ${EXCHCXX_SOURCES} )
 # TARGET properties
 
 target_compile_features( exchcxx PUBLIC cxx_std_17 )
+if(MSVC)
+  target_compile_definitions( exchcxx PUBLIC _USE_MATH_DEFINES )
+  if(CMAKE_CXX_COMPILER_ID MATCHES "Clang")  # clang-cl
+    target_compile_options( exchcxx PRIVATE
+      -Wno-sign-conversion   # mirrors /wd4365: signed/unsigned in STL-heavy code
+      -Wno-switch-enum       # mirrors /wd4061: intentional default: covers all kernels
+    )
+  else()  # cl
+    target_compile_options( exchcxx PUBLIC
+      /Zc:preprocessor  # PUBLIC: public headers use NOTYPE empty macro; consumers need conforming preprocessor
+    )
+    # silence noisy level-4 warnings that appear because STL raises the level to 4 during template instantiations
+    target_compile_options( exchcxx PRIVATE
+      /wd4061  # enumerator not in switch case: intentional default: handler covers all kernels
+      /wd4266  # no override for virtual function: by-design partial override in APPROX specialisations
+      /wd4365  # signed/unsigned in STL code: safe, values always non-negative
+      /wd4514  # unreferenced inline removed: informational, linker dead-strips correctly
+      /wd4626  # assignment operator deleted: by-design non-copyable classes with reference members
+      /wd4702  # unreachable code: macro-expanded dispatch tables, not real dead code
+      /wd4710  # function not inlined: informational, optimizer decision
+      /wd4711  # function auto-inlined: informational, optimizer decision
+      /wd4800  # implicit double-to-bool: fires in auto-generated kernel headers, intentional
+      /wd4820  # struct padding: ABI layout decision, informational
+      /wd5045  # Spectre mitigation remark: informational, /Qspectre not in use
+    )
+  endif()
+endif()
 if( EXCHCXX_ENABLE_LIBXC )
   target_link_libraries( exchcxx PUBLIC Libxc::xc )
 endif()
@@ -28,7 +55,6 @@ configure_file(
 target_compile_definitions( exchcxx PUBLIC "EXCHCXX_HAS_CONFIG_H=1" )
 
 
-
 # Device specific
 if( EXCHCXX_ENABLE_CUDA )
   include( cuda/exchcxx_cuda.cmake )
@@ -43,7 +69,6 @@ if( EXCHCXX_ENABLE_SYCL )
 endif()
 
 
-
 target_include_directories( exchcxx
   PUBLIC
     $<INSTALL_INTERFACE:include>
@@ -53,7 +78,9 @@ target_include_directories( exchcxx
 )
 
 include( CheckCXXCompilerFlag )
-check_cxx_compiler_flag( -Wall              EXCHCXX_CXX_HAS_WALL              )
+if(NOT MSVC)  # under clang-cl, -Wall maps to /Wall (= -Weverything)
+  check_cxx_compiler_flag( -Wall              EXCHCXX_CXX_HAS_WALL              )
+endif()
 check_cxx_compiler_flag( -Wextra            EXCHCXX_CXX_HAS_WEXTRA            )
 check_cxx_compiler_flag( -Wpedantic         EXCHCXX_CXX_HAS_WPEDANTIC         )
 check_cxx_compiler_flag( -Wnon-virtual-dtor EXCHCXX_CXX_HAS_WNON_VIRTUAL_DTOR )
@@ -79,10 +106,10 @@ if( EXCHCXX_CXX_HAS_WSHADOW )
   target_compile_options( exchcxx PRIVATE $<$<COMPILE_LANGUAGE:CXX>: -Wshadow -Werror=shadow> )
 endif()
 
+
 # INSTALL rules
 add_library( ExchCXX::ExchCXX ALIAS exchcxx )
 
-
 include( GNUInstallDirs )
 set( INSTALL_CONFIGDIR ${CMAKE_INSTALL_LIBDIR}/cmake/ExchCXX )
 
@@ -93,7 +120,6 @@ install(TARGETS exchcxx
     ARCHIVE DESTINATION ${CMAKE_INSTALL_LIBDIR}
 )
 
-
 set_target_properties( exchcxx PROPERTIES EXPORT_NAME ExchCXX )
 
 # Install Headers

src/builtin_interface.cxx

@@ -67,7 +67,7 @@ std::unique_ptr<BuiltinKernel>
 
   // Bail if polarized eval is requested and not supported
   EXCHCXX_BOOL_CHECK(kernel_map.key(kern) + " Needs to be Spin-Polarized!",
-                     supports_unpolarized(kern) or polar == Spin::Polarized);
+                     supports_unpolarized(kern) || polar == Spin::Polarized);
 
   if( kern == Kernel::SlaterExchange )
     return std::make_unique<BuiltinSlaterExchange>( polar );

src/libxc.cxx

@@ -256,21 +256,21 @@ std::unique_ptr< XCKernelImpl > LibxcKernelImpl::clone_() const {
 bool LibxcKernelImpl::is_lda_() const noexcept {
   return (kernel_.info->family == XC_FAMILY_LDA) 
 #if XC_MAJOR_VERSION > 6
-  or (kernel_.info->family == XC_FAMILY_HYB_LDA)
+  || (kernel_.info->family == XC_FAMILY_HYB_LDA)
 #endif
   ;
 }
 
 bool LibxcKernelImpl::is_gga_() const noexcept {
   return 
     (kernel_.info->family == XC_FAMILY_GGA    ) 
-    or (kernel_.info->family == XC_FAMILY_HYB_GGA);
+    || (kernel_.info->family == XC_FAMILY_HYB_GGA);
 }
 
 bool LibxcKernelImpl::is_mgga_() const noexcept {
   return 
     (kernel_.info->family == XC_FAMILY_MGGA    )
-    or (kernel_.info->family == XC_FAMILY_HYB_MGGA);
+    || (kernel_.info->family == XC_FAMILY_HYB_MGGA);
 }
 
 bool LibxcKernelImpl::needs_laplacian_() const noexcept {
@@ -291,12 +291,11 @@ bool LibxcKernelImpl::is_polarized_() const noexcept {
 }
 
 bool LibxcKernelImpl::is_epc_() const noexcept {
-  int xcNumber = xc_info()->number;
-  return
 #if XC_MAJOR_VERSION > 7
-  xcNumber == XC_LDA_C_EPC17 or xcNumber == XC_LDA_C_EPC17_2 or xcNumber == XC_LDA_C_EPC18_1 or xcNumber == XC_LDA_C_EPC18_2;
+  int xcNumber = xc_info()->number;
+  return xcNumber == XC_LDA_C_EPC17 || xcNumber == XC_LDA_C_EPC17_2 || xcNumber == XC_LDA_C_EPC18_1 || xcNumber == XC_LDA_C_EPC18_2;
 #else
-  false;
+  return false;
 #endif
 }