From b3e9e62599532050fc776c5e8f076915b56c2235 Mon Sep 17 00:00:00 2001
From: David Faulkner <d@davo.co>
Date: Fri, 7 Aug 2026 23:40:47 -0500
Subject: Import official C23 code examples for Modern C (Jens Gustedt, 2024)

- Add official C source files, Makefile, c23-fallback.h, and LICENSE
- Update README.md with study mirror notice
---
 shadow.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)
 create mode 100644 shadow.c

(limited to 'shadow.c')

diff --git a/shadow.c b/shadow.c
new file mode 100644
index 0000000..f996fc8
--- /dev/null
+++ b/shadow.c
@@ -0,0 +1,20 @@
+#include "c23-fallback.h"
+
+void squareIt(double* p) [[__unsequenced__]] {
+  *p *= *p;
+}
+int main(void) {
+  double x = 35.0; /*@\label{line:decl-x}*/
+  double* xp = &x; /*@\label{line:decl-xp}*/
+  {
+    squareIt(&x);               /* Refers to double x *//*@\label{line:use-x-1}*/
+    /*@…*/
+    [[maybe_unused]] int x = 0; /* Shadow double x *//*@\label{line:decl-x-2}*/
+    /*@…*/
+    squareIt(xp);               /* Valid use of double x *//*@\label{line:use-xp}*/
+    /*@…*/
+  }                /*@\label{line:end-x-2}*/
+  /*@…*/
+  squareIt(&x);                 /* Refers to double x *//*@\label{line:use-x-2}*/
+  /*@…*/
+}
-- 
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