# C#/.NET System namespace support Burst provides support for some of the `System` namespace, transforming these into Burst compatible variants in the Burst compiler. ## System.Math Burst supports all methods that `System.Math` declares, with the following exceptions: - `double IEEERemainder(double x, double y)` is only supported when Api Compatibility Level is set to .NET Standard 2.1 in project settings ## System.IntPtr Burst supports all methods of `System.IntPtr`/`System.UIntPtr`, including the static fields `IntPtr.Zero` and `IntPtr.Size` ## System.Threading.Interlocked Burst supports atomic memory intrinsics for all methods provided by `System.Threading.Interlocked` (for example, `Interlocked.Increment`). Make sure that the source location of the interlocked methods are naturally aligned. For example, the alignment of the pointer is a multiple of the pointed-to-type: ```c# [StructLayout(LayoutKind.Explicit)] struct Foo { [FieldOffset(0)] public long a; [FieldOffset(5)] public long b; public long AtomicReadAndAdd() { return Interlocked.Read(ref a) + Interlocked.Read(ref b); } } ``` If the pointer to the struct `Foo` has an alignment of 8, which is the natural alignment of a `long` value, the `Interlocked.Read` of `a` would be successful because it lies on a naturally aligned address. However, `b` would not be successful and undefined behavior happens at the load of `b` as a result. ## System.Threading.Thread Burst supports the `MemoryBarrier` method of `System.Threading.Thread`. ## System.Threading.Volatile Burst supports the non-generic variants of `Read` and `Write` provided by `System.Threading.Volatile`. ## System.HashCode Burst supports all methods of `HashCode` except for `HashCode.Add(T, IEqualityComparer)`. Do note that Burst does not follow .NET's implementation in sense of only being deterministic within a specific operating system process. ## Additional resources * [HPC# overview](csharp-hpc-overview.md) * [String support](csharp-string-support.md) * [C#/.NET type support](csharp-type-support.md)