Test public headers for shadowed variables (STR 2728)

This program is built only when using CMake and a GNU or Clang
compiler to detect shadowed variables in header files.

Developers should fix such warnings whenever they see them during the
build to avoid user reports.

1 files changed, 29 insertions, 0 deletions

diff --git a/test/shadow_variables.cxx b/test/shadow_variables.cxx
new file mode 100644
index 000000000..7690c1d11
--- /dev/null
+++ b/test/shadow_variables.cxx
@@ -0,0 +1,29 @@
+//
+// Public header compilation test program for the Fast Light Tool Kit (FLTK).
+//
+// Copyright 1998-2024 by Bill Spitzak and others.
+//
+// This library is free software. Distribution and use rights are outlined in
+// the file "COPYING" which should have been included with this file.  If this
+// file is missing or damaged, see the license at:
+//
+//     https://www.fltk.org/COPYING.php
+//
+// Please see the following page on how to report bugs and issues:
+//
+//     https://www.fltk.org/bugs.php
+//
+
+// The following header file is generated by CMake and includes all
+// public FLTK headers:
+
+#include "include_all.h"
+
+#include <stdio.h>
+
+int main() {
+  printf("This program includes all FLTK header files for compilation.\n");
+  printf("It should be compiled with `g++ (clang++) -Wshadow ...` or similar.\n");
+  printf("This program does nothing.\n");
+  return 0;
+}