diff --git a/src/stdplus/fd/impl.hpp b/src/stdplus/fd/impl.hpp
new file mode 100644
index 0000000..b321dfb
--- /dev/null
+++ b/src/stdplus/fd/impl.hpp
@@ -0,0 +1,36 @@
+#pragma once
+#include <stdplus/fd/intf.hpp>
+
+namespace stdplus
+{
+namespace fd
+{
+
+class FdImpl : public Fd
+{
+  public:
+    virtual int get() const = 0;
+
+    span<std::byte> read(span<std::byte> buf) override;
+    span<std::byte> recv(span<std::byte> buf, RecvFlags flags) override;
+    span<const std::byte> write(span<const std::byte> data) override;
+    span<const std::byte> send(span<const std::byte> data,
+                               SendFlags flags) override;
+    size_t lseek(off_t offset, Whence whence) override;
+    void truncate(off_t size) override;
+    void bind(span<const std::byte> sockaddr) override;
+    void setsockopt(SockLevel level, SockOpt optname,
+                    span<const std::byte> opt) override;
+    int ioctl(unsigned long id, void* data) override;
+    int constIoctl(unsigned long id, void* data) const override;
+    void fcntlSetfd(FdFlags flags) override;
+    FdFlags fcntlGetfd() const override;
+    void fcntlSetfl(FileFlags flags) override;
+    FileFlags fcntlGetfl() const override;
+};
+
+} // namespace fd
+
+using fd::FdImpl;
+
+} // namespace stdplus