1 files changed, 20 insertions, 0 deletions
diff --git a/src/net/fcntl_syscall_test.go b/src/net/fcntl_syscall_test.go
new file mode 100644
index 0000000..b9ac1d3
--- /dev/null
+++ b/src/net/fcntl_syscall_test.go
@@ -0,0 +1,20 @@
+// Copyright 2021 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+//go:build dragonfly || freebsd || linux || netbsd || (openbsd && mips64)
+
+package net
+
+import (
+	"internal/syscall/unix"
+	"syscall"
+)
+
+func fcntl(fd int, cmd int, arg int) (int, error) {
+	r, _, e := syscall.Syscall(unix.FcntlSyscall, uintptr(fd), uintptr(cmd), uintptr(arg))
+	if e != 0 {
+		return int(r), syscall.Errno(e)
+	}
+	return int(r), nil
+}