diff --git a/lib/std/c/freebsd.zig b/lib/std/c/freebsd.zig
index 57fe14f194..28d759ddc7 100644
--- a/lib/std/c/freebsd.zig
+++ b/lib/std/c/freebsd.zig
@@ -15,6 +15,7 @@ pub extern "c" fn pthread_getthreadid_np() c_int;
 pub extern "c" fn pthread_set_name_np(thread: std.c.pthread_t, name: [*:0]const u8) void;
 pub extern "c" fn pthread_get_name_np(thread: std.c.pthread_t, name: [*:0]u8, len: usize) void;
 pub extern "c" fn pipe2(fds: *[2]fd_t, flags: u32) c_int;
+pub extern "c" fn arc4random_buf(buf: [*]u8, len: usize) void;
 
 pub extern "c" fn posix_memalign(memptr: *?*anyopaque, alignment: usize, size: usize) c_int;
 pub extern "c" fn malloc_usable_size(?*const anyopaque) usize;