+#![stable(feature = "", since = "1.30.0")]
+
+#![allow(non_camel_case_types)]
+
+//! Utilities related to FFI bindings.
+
+use ::fmt;
+
+/// Equivalent to C's `void` type when used as a [pointer].
+///
+/// In essence, `*const c_void` is equivalent to C's `const void*`
+/// and `*mut c_void` is equivalent to C's `void*`. That said, this is
+/// *not* the same as C's `void` return type, which is Rust's `()` type.
+///
+/// Ideally, this type would be equivalent to [`!`], but currently it may
+/// be more ideal to use `c_void` for FFI purposes.
+///
+/// [`!`]: ../../std/primitive.never.html
+/// [pointer]: ../../std/primitive.pointer.html
+// NB: For LLVM to recognize the void pointer type and by extension
+// functions like malloc(), we need to have it represented as i8* in
+// LLVM bitcode. The enum used here ensures this and prevents misuse
+// of the "raw" type by only having private variants.. We need two
+// variants, because the compiler complains about the repr attribute
+// otherwise.
+#[repr(u8)]
+#[stable(feature = "raw_os", since = "1.1.0")]
+pub enum c_void {
+ #[unstable(feature = "c_void_variant", reason = "should not have to exist",
+ issue = "0")]
+ #[doc(hidden)] __variant1,
+ #[unstable(feature = "c_void_variant", reason = "should not have to exist",
+ issue = "0")]
+ #[doc(hidden)] __variant2,
+}
+
+#[stable(feature = "std_debug", since = "1.16.0")]
+impl fmt::Debug for c_void {
+ fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+ f.pad("c_void")
+ }
+}