kernel: move device_number to kapi

2 files changed, 27 insertions, 0 deletions

diff --git a/kapi/kapi/filesystem.hpp b/kapi/kapi/filesystem.hpp
index f293692d..b64d251d 100644
--- a/kapi/kapi/filesystem.hpp
+++ b/kapi/kapi/filesystem.hpp
@@ -1,6 +1,8 @@
 #ifndef TEACHOS_KAPI_FILESYSTEM_HPP
 #define TEACHOS_KAPI_FILESYSTEM_HPP
 
+#include <kapi/filesystem/device_number.hpp>  // IWYU pragma: export
+
 #include <kstd/result.hpp>
 #include <kstd/system_error.hpp>
 #include <kstd/units.hpp>
diff --git a/kapi/kapi/filesystem/device_number.hpp b/kapi/kapi/filesystem/device_number.hpp
new file mode 100644
index 00000000..55c813f5
--- /dev/null
+++ b/kapi/kapi/filesystem/device_number.hpp
@@ -0,0 +1,25 @@
+#ifndef TEACHOS_KAPI_FILESYSTEM_DEVICE_NUMBER_HPP
+#define TEACHOS_KAPI_FILESYSTEM_DEVICE_NUMBER_HPP
+
+// IWYU pragma: private, include <kapi/filesystem.hpp>
+
+#include <compare>
+#include <cstdint>
+
+namespace kapi::filesystem
+{
+
+  //! A POSIX device number.
+  struct device_number
+  {
+    //! The major number, identifying the device class or driver.
+    std::uint8_t major;
+    //! The minor number, identifying the device instance.
+    std::uint8_t minor;
+
+    constexpr auto friend operator<=>(device_number, device_number) noexcept -> std::strong_ordering = default;
+  };
+
+}  // namespace kapi::filesystem
+
+#endif