Switch P/Invokes to use LibraryImport in .NET 7.0 and above.

src/Prometheus.SystemMetrics/Collectors/WindowsMemoryCollector.cs

@@ -105,9 +105,9 @@ public void CreateMetrics(MetricFactory factory)
 		/// </summary>
 		public void UpdateMetrics()
 		{
-			var memStatus = new MEMORYSTATUSEX();
+			var memStatus = new MemoryStatusEx();
 
-			if (!WindowsNative.GlobalMemoryStatusEx(memStatus))
+			if (!WindowsNative.GlobalMemoryStatusEx(ref memStatus))
 			{
 				throw new Exception(Marshal.GetLastWin32Error().ToString());
 			}

src/Prometheus.SystemMetrics/Native/LinuxNative.cs

@@ -5,16 +5,26 @@ namespace Prometheus.SystemMetrics.Native
 	/// <summary>
 	/// Native API calls for Linux.
 	/// </summary>
-	internal static class LinuxNative
+	internal static partial class LinuxNative
 	{
 		public const int SC_CLK_TCK = 0x2;
 
+#if NET7_0_OR_GREATER
+		[LibraryImport("libc", SetLastError = true)]
+		[DefaultDllImportSearchPaths(DllImportSearchPath.SafeDirectories)]
+		internal static partial int getloadavg(double[] loadavg, int nelem);
+
+		[LibraryImport("libc", SetLastError = true)]
+		[DefaultDllImportSearchPaths(DllImportSearchPath.SafeDirectories)]
+		internal static partial long sysconf(int name);
+#else
 		[DllImport("libc", SetLastError = true)]
 		[DefaultDllImportSearchPaths(DllImportSearchPath.SafeDirectories)]
 		internal static extern int getloadavg(double[] loadavg, int nelem);
 
 		[DllImport("libc", SetLastError = true)]
 		[DefaultDllImportSearchPaths(DllImportSearchPath.SafeDirectories)]
-		public static extern long sysconf(int name);
+		internal static extern long sysconf(int name);
+#endif
 	}
 }

src/Prometheus.SystemMetrics/Native/WindowsNative.cs

@@ -5,23 +5,35 @@ namespace Prometheus.SystemMetrics.Native
 	/// <summary>
 	/// Native API calls for Windows.
 	/// </summary>
-	internal static class WindowsNative
+	internal static partial class WindowsNative
 	{
+#if NET7_0_OR_GREATER
+		/// <summary>
+		/// Retrieves information about the system's current usage of both physical and virtual memory.
+		/// See https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-globalmemorystatusex
+		/// </summary>
+		[return: MarshalAs(UnmanagedType.Bool)]
+		[LibraryImport("kernel32.dll", SetLastError = true)]
+		[DefaultDllImportSearchPaths(DllImportSearchPath.SafeDirectories)]
+		internal static partial bool GlobalMemoryStatusEx(ref MemoryStatusEx lpBuffer);
+#else
 		/// <summary>
 		/// Retrieves information about the system's current usage of both physical and virtual memory.
 		/// See https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/nf-sysinfoapi-globalmemorystatusex
 		/// </summary>
 		[return: MarshalAs(UnmanagedType.Bool)]
 		[DllImport("kernel32.dll", CharSet = CharSet.Auto, SetLastError = true)]
-		internal static extern bool GlobalMemoryStatusEx([In, Out] MEMORYSTATUSEX lpBuffer);
+		[DefaultDllImportSearchPaths(DllImportSearchPath.SafeDirectories)]
+		internal static extern bool GlobalMemoryStatusEx(ref MemoryStatusEx lpBuffer);
+#endif
 	}
 
 	/// <summary>
 	/// Contains information about the current state of both physical and virtual memory, including extended memory.
 	/// See https://docs.microsoft.com/en-us/windows/win32/api/sysinfoapi/ns-sysinfoapi-memorystatusex
 	/// </summary>
 	[StructLayout(LayoutKind.Sequential, CharSet = CharSet.Auto)]
-	public class MEMORYSTATUSEX
+	internal struct MemoryStatusEx
 	{
 		/// <summary>
 		/// The size of the structure, in bytes. You must set this member before calling 
@@ -83,11 +95,11 @@ public class MEMORYSTATUSEX
 		public ulong ullAvailExtendedVirtual;
 
 		/// <summary>
-		/// Creates a new instance of <see cref="MEMORYSTATUSEX"/>.
+		/// Creates a new instance of <see cref="MemoryStatusEx"/>.
 		/// </summary>
-		public MEMORYSTATUSEX()
+		public MemoryStatusEx()
 		{
-			dwLength = (uint)Marshal.SizeOf<MEMORYSTATUSEX>();
+			dwLength = (uint)Marshal.SizeOf<MemoryStatusEx>();
 		}
 	}
 }

src/Prometheus.SystemMetrics/Prometheus.SystemMetrics.csproj

@@ -5,6 +5,8 @@
     <Nullable>enable</Nullable>
     <LangVersion>latestMajor</LangVersion>
     <IsAotCompatible Condition="$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net7.0'))">true</IsAotCompatible>
+    <!-- Required by LibraryImport -->
+    <AllowUnsafeBlocks>true</AllowUnsafeBlocks>
     <PackageId>prometheus-net.SystemMetrics</PackageId>
     <Product>prometheus-net.SystemMetrics</Product>
     <Authors>Daniel Lo Nigro</Authors>