Update to .NET 7 paths and add error reporting

core/nativeaot/NativeLibrary/LibraryFunctions.cs

@@ -0,0 +1,54 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+using System;
+using System.Runtime.InteropServices;
+
+namespace NativeLibrary;
+
+public class LibraryFunctions
+{
+    [UnmanagedCallersOnly(EntryPoint = "add")]
+    public static int Add(int a, int b)
+    {
+        return a + b;
+    }
+
+    [UnmanagedCallersOnly(EntryPoint = "write_line")]
+    public static int WriteLine(IntPtr pString)
+    {
+        // The marshalling code is typically auto-generated by a custom tool in larger projects.
+        try
+        {
+            // UnmanagedCallersOnly methods only accept primitive arguments. The primitive arguments
+            // have to be marshalled manually if necessary.
+            string str = Marshal.PtrToStringAnsi(pString);
+
+            Console.WriteLine(str);
+        }
+        catch
+        {
+            // Exceptions escaping out of UnmanagedCallersOnly methods are treated as unhandled exceptions.
+            // The errors have to be marshalled manually if necessary.
+            return -1;
+        }
+        return 0;
+    }
+
+    [UnmanagedCallersOnly(EntryPoint = "sumstring")]
+    public static IntPtr sumstring(IntPtr first, IntPtr second)
+    {
+        // Parse strings from the passed pointers 
+        string my1String = Marshal.PtrToStringAnsi(first);
+        string my2String = Marshal.PtrToStringAnsi(second);
+
+        // Concatenate strings 
+        string sum = my1String + my2String;
+
+        // Assign pointer of the concatenated string to sumPointer
+        IntPtr sumPointer = Marshal.StringToHGlobalAnsi(sum);
+
+        // Return pointer
+        return sumPointer;
+    }
+}

core/nativeaot/NativeLibrary/LoadLibrary.c

@@ -5,11 +5,11 @@
 
 //Set this value accordingly to your workspace settings
 #if defined(_WIN32)
-#define PathToLibrary "bin\\Debug\\net6.0\\win-x64\\native\\NativeLibrary.dll"
+#define PathToLibrary "bin\\Debug\\net7.0\\win-x64\\native\\NativeLibrary.dll"
 #elif defined(__APPLE__)
-#define PathToLibrary "./bin/Debug/net6.0/osx-x64/native/NativeLibrary.dylib"
+#define PathToLibrary "./bin/Debug/net7.0/osx-x64/native/NativeLibrary.dylib"
 #else
-#define PathToLibrary "./bin/Debug/net6.0/linux-x64/native/NativeLibrary.so"
+#define PathToLibrary "./bin/Debug/net7.0/linux-x64/native/NativeLibrary.so"
 #endif
 
 #ifdef _WIN32
@@ -31,6 +31,8 @@
 int callSumFunc(char *path, char *funcName, int a, int b);
 char *callSumStringFunc(char *path, char *funcName, char *a, char *b);
 
+void* loadSymbol(char *path, char *funcName);
+
 int main()
 {
     // Check if the library file exists
@@ -52,44 +54,53 @@ int main()
     free(sumstring);
 }
 
-int callSumFunc(char *path, char *funcName, int firstInt, int secondInt)
+void *loadSymbol(char *path, char *funcName)
 {
-    // Call sum function defined in C# shared library
+    // Library loading
     #ifdef _WIN32
         HINSTANCE handle = LoadLibraryA(path);
     #else
         void *handle = dlopen(path, RTLD_LAZY);
     #endif
+    if (!handle)
+    {
+#ifdef _WIN32
+        int errorCode = GetLastError();
+        printf("Failed to load library at specified path. Error code: %d\n", errorCode);
+#else
+        puts("Failed to load library at specified path");
+#endif
+        return NULL;
+    }
 
-    typedef int(*myFunc)(int,int);
-    myFunc MyImport = (myFunc)symLoad(handle, funcName);
+    // Declare a typedef
+    typedef char *(*myFunc)(char*,char*);
 
-    int result = MyImport(firstInt, secondInt);
+    // Import Symbol named funcName
 
-    // CoreRT libraries do not support unloading
+    // NativeAOT libraries do not support unloading
     // See https://github.com/dotnet/corert/issues/7887
+    return symLoad(handle, funcName);
+}
+
+int callSumFunc(char *path, char *funcName, int firstInt, int secondInt)
+{
+    typedef int(*myFunc)(int,int);
+    myFunc MyImport = (myFunc)loadSymbol(path, funcName);
+
+    int result = MyImport(firstInt, secondInt);
     return result;
 }
 
 char *callSumStringFunc(char *path, char *funcName, char *firstString, char *secondString)
 {
-    // Library loading
-    #ifdef _WIN32
-        HINSTANCE handle = LoadLibraryA(path);
-    #else
-        void *handle = dlopen(path, RTLD_LAZY);
-    #endif
-
     // Declare a typedef
     typedef char *(*myFunc)(char*,char*);
 
     // Import Symbol named funcName
-    myFunc MyImport = (myFunc)symLoad(handle, funcName);
+    myFunc MyImport = (myFunc)loadSymbol(path, funcName);
 
     // The C# function will return a pointer
     char *result = MyImport(firstString, secondString);
-
-    // CoreRT libraries do not support unloading
-    // See https://github.com/dotnet/corert/issues/7887
     return result;
 }