From 20a8ac0263958eeb1289284733888e29583f2acb Mon Sep 17 00:00:00 2001
From: Cristian Le <cristian.le@mpsd.mpg.de>
Date: Mon, 19 Jun 2023 14:08:43 +0200
Subject: [PATCH] Document minimum C standard

Signed-off-by: Cristian Le <cristian.le@mpsd.mpg.de>
---
 README.md    | 5 +++++
 doc/index.md | 5 +++++
 2 files changed, 10 insertions(+)

diff --git a/README.md b/README.md
index b09f7294f..3384ebdb4 100644
--- a/README.md
+++ b/README.md
@@ -66,6 +66,11 @@ int main(void) {
 }
 ```
 
+## Requirements
+
+- C standard: As of version 2.1.0, Spglib explicitly enforces a minimum standard of
+  [C11](https://en.cppreference.com/w/c/11)
+
 ## How to use Spglib
 
 We currently only officially support conda and pip packaging of spglib, with plans
diff --git a/doc/index.md b/doc/index.md
index e233de443..c36fc1945 100644
--- a/doc/index.md
+++ b/doc/index.md
@@ -28,6 +28,11 @@ The detailed algorithm of spglib is described the following text:
   Atsushi Togo and Isao Tanaka,
   <https://arxiv.org/abs/1808.01590> (written at version 1.10.4)
 
+## Requirements
+
+- C standard: As of version 2.1.0, Spglib explicitly enforces a minimum standard of
+  [C11](https://en.cppreference.com/w/c/11)
+
 ## Features
 
 - Find symmetry operations