1 files changed, 40 insertions, 0 deletions
diff --git a/library/std/src/sys/sync/rwlock/windows7.rs b/library/std/src/sys/sync/rwlock/windows7.rs
new file mode 100644
index 00000000000..e69415baac4
--- /dev/null
+++ b/library/std/src/sys/sync/rwlock/windows7.rs
@@ -0,0 +1,40 @@
+use crate::cell::UnsafeCell;
+use crate::sys::c;
+
+pub struct RwLock {
+    inner: UnsafeCell<c::SRWLOCK>,
+}
+
+unsafe impl Send for RwLock {}
+unsafe impl Sync for RwLock {}
+
+impl RwLock {
+    #[inline]
+    pub const fn new() -> RwLock {
+        RwLock { inner: UnsafeCell::new(c::SRWLOCK_INIT) }
+    }
+    #[inline]
+    pub fn read(&self) {
+        unsafe { c::AcquireSRWLockShared(self.inner.get()) }
+    }
+    #[inline]
+    pub fn try_read(&self) -> bool {
+        unsafe { c::TryAcquireSRWLockShared(self.inner.get()) != 0 }
+    }
+    #[inline]
+    pub fn write(&self) {
+        unsafe { c::AcquireSRWLockExclusive(self.inner.get()) }
+    }
+    #[inline]
+    pub fn try_write(&self) -> bool {
+        unsafe { c::TryAcquireSRWLockExclusive(self.inner.get()) != 0 }
+    }
+    #[inline]
+    pub unsafe fn read_unlock(&self) {
+        c::ReleaseSRWLockShared(self.inner.get())
+    }
+    #[inline]
+    pub unsafe fn write_unlock(&self) {
+        c::ReleaseSRWLockExclusive(self.inner.get())
+    }
+}