1 files changed, 23 insertions, 0 deletions
diff --git a/libc/src/threads/call_once.cpp b/libc/src/threads/call_once.cpp
new file mode 100644
index 000000000000..67ab34509a4c
--- /dev/null
+++ b/libc/src/threads/call_once.cpp
@@ -0,0 +1,23 @@
+//===-- Linux implementation of the call_once function --------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "src/threads/call_once.h"
+#include "src/__support/common.h"
+#include "src/__support/threads/callonce.h"
+
+#include <threads.h> // For once_flag and __call_once_func_t definitions.
+
+namespace __llvm_libc {
+
+LLVM_LIBC_FUNCTION(void, call_once,
+                   (once_flag * flag, __call_once_func_t func)) {
+  callonce(reinterpret_cast<CallOnceFlag *>(flag),
+           reinterpret_cast<CallOnceCallback *>(func));
+}
+
+} // namespace __llvm_libc