csharp call c++ library

.github/workflows/macos.yml

@@ -25,6 +25,7 @@ jobs:
           # WyriHaximus/github-action-get-previous-tag@master need it
           fetch-depth: 0
           submodules: true
+
       - name: Prepare local xmake
         run: cp -rf . ../xmake-source
       - uses: xmake-io/github-action-setup-xmake@v1

tests/projects/csharp/pinvoke/src/app/Program.cs

@@ -0,0 +1,16 @@
+using System.Runtime.InteropServices;
+
+int sum = NativeMethods.add(3, 4);
+int product = NativeMethods.multiply(5, 6);
+Console.WriteLine($"add(3,4)={sum}");
+Console.WriteLine($"multiply(5,6)={product}");
+
+internal static class NativeMethods {
+    private const string NativeLib = "mathlib";
+
+    [DllImport(NativeLib)]
+    internal static extern int add(int a, int b);
+
+    [DllImport(NativeLib)]
+    internal static extern int multiply(int a, int b);
+}

tests/projects/csharp/pinvoke/src/native/mathlib.c

@@ -0,0 +1,13 @@
+#ifdef _WIN32
+#define EXPORT __declspec(dllexport)
+#else
+#define EXPORT __attribute__((visibility("default")))
+#endif
+
+EXPORT int add(int a, int b) {
+    return a + b;
+}
+
+EXPORT int multiply(int a, int b) {
+    return a * b;
+}

tests/projects/csharp/pinvoke/test.lua

@@ -0,0 +1,13 @@
+import("detect.sdks.find_dotnet")
+
+function test_build(t)
+    if is_subhost("msys") then
+        return t:skip("csharp not supported on msys")
+    end
+    local dotnet = find_dotnet()
+    if dotnet and dotnet.sdkver then
+        t:build()
+    else
+        return t:skip("dotnet sdk not found")
+    end
+end

tests/projects/csharp/pinvoke/xmake.lua

@@ -0,0 +1,10 @@
+add_rules("mode.debug", "mode.release")
+
+target("mathlib")
+    set_kind("shared")
+    add_files("src/native/*.c")
+
+target("app")
+    set_kind("binary")
+    add_deps("mathlib")
+    add_files("src/app/*.cs")

xmake/rules/csharp/config.lua

@@ -44,4 +44,17 @@ function main(target)
     end, {dependfile = dependfile, files = sourcefiles, values = depcsproj})
 
     target:data_set("csharp.csproj", csprojfile)
+
+    -- add native shared library search paths for P/Invoke
+    for _, dep in ipairs(target:orderdeps()) do
+        if dep:is_shared() and not dep:rule("csharp.build") then
+            if is_host("windows") then
+                target:add("runenvs", "PATH", dep:targetdir())
+            elseif is_host("macosx") then
+                target:add("runenvs", "DYLD_LIBRARY_PATH", dep:targetdir())
+            else
+                target:add("runenvs", "LD_LIBRARY_PATH", dep:targetdir())
+            end
+        end
+    end
 end

xmake/rules/csharp/generator/properties.lua

@@ -67,6 +67,8 @@ function _resolve_assembly_name(context)
 end
 
 
+-- resolve runtime identifier from user config or auto-detect from target plat/arch
+-- e.g. "osx-x64", "osx-arm64", "linux-x64", "win-x64"
 -- register a single-value csharp.* property entry
 function _register_property(register, suffix, xml, default, extra)
     local entry = table.join({