diff --git a/nonstd.h b/nonstd.h
index 3e39380e7edf59c3af8515e177b80e42d0310e52..d001a4a99dc938dafeaf9c3c753427a9a0566ed3 100644
--- a/nonstd.h
+++ b/nonstd.h
@@ -1,3 +1,12 @@
+// nonstd.h
+// A collection of useful functions and macros.
+// This library is licensed under the BSD 2-Clause License.
+// 
+// This file provides both the interface and the implementation.
+// To instantiate the implementation,
+//     #define NONSTD_IMPLEMENTATION
+//  before including this file.
+
 #ifdef NONSTD_IMPLEMENTATION
 #ifndef _POSIX_C_SOURCE
 #define _POSIX_C_SOURCE 200809L
@@ -795,4 +804,31 @@ 	ppm_draw_line(canvas, x1, y1, x2, y2, color);
 	ppm_draw_line(canvas, x2, y2, x0, y0, color);
 }
 
-#endif // NONSTD_IMPLEMENTATION
\ No newline at end of file
+#endif // NONSTD_IMPLEMENTATION
+
+/*
+BSD 2-Clause License
+
+Copyright (c) 2026, Mitja Felicijan <mitja.felicijan@gmail.com>
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice, this
+   list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
\ No newline at end of file