Support import std for CMake

install.sh

@@ -164,6 +164,9 @@ fi
 MSVCVER=$(basename $(echo vc/tools/msvc/* | awk '{print $1}'))
 echo Using MSVC version $MSVCVER
 
+# Support `import std` for CMake.
+ln_s VC/Tools/MSVC/$MSVCVER/modules modules
+
 cat $ORIG/wrappers/msvcenv.sh \
 | sed 's/MSVCVER=.*/MSVCVER='$MSVCVER/ \
 | sed 's/SDKVER=.*/SDKVER='$SDKVER/ \

test/CMakeLists.txt

@@ -7,6 +7,14 @@ if (WIN32)
 endif()
 add_executable(hello ${hello_SOURCES})
 
+if(TARGET __CMAKE::CXX23) # Since cmake 3.30
+    add_executable(hello-cxx23 hello.cpp)
+    target_compile_features(hello-cxx23 PUBLIC cxx_std_23)
+    set_target_properties(hello-cxx23 PROPERTIES
+        CXX_SCAN_FOR_MODULES ON
+        CXX_MODULE_STD ON
+    )
+endif()
 
 if(CMAKE_CXX_COMPILER_ID STREQUAL "MSVC" AND DEFINED MSVCDIR)
     add_library(cxxmodules STATIC "${MSVCDIR}/modules/std.ixx")

test/hello.cpp

@@ -0,0 +1,6 @@
+import std;
+
+int main()
+{
+    std::println("{}", "Hello world!");
+}

test/test-cmake.sh

@@ -41,9 +41,7 @@ EXEC "" ninja -v
 
 # Rerun ninja to make sure that dependencies aren't broken.
 EXEC ninja-rerun ninja -d explain -v
-DIFF ninja-rerun.err - <<EOF
-EOF
-DIFF ninja-rerun.out - <<EOF
+DIFF ninja-rerun.out - <<EOF || cat ninja-rerun.err
 ninja: no work to do.
 EOF