1 files changed, 33 insertions, 0 deletions
diff --git a/misc/sys/single_threaded.h b/misc/sys/single_threaded.h
new file mode 100644
index 0000000000..648fc2e00a
--- /dev/null
+++ b/misc/sys/single_threaded.h
@@ -0,0 +1,33 @@
+/* Support for single-thread optimizations.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#ifndef _SYS_SINGLE_THREADED_H
+#define _SYS_SINGLE_THREADED_H
+
+#include <features.h>
+
+__BEGIN_DECLS
+
+/* If this variable is non-zero, then the current thread is the only
+   thread in the process image.  If it is zero, the process might be
+   multi-threaded.  */
+extern char __libc_single_threaded;
+
+__END_DECLS
+
+#endif /* _SYS_SINGLE_THREADED_H */