Do not rely on a define for disabling warnings
Using a define to determine whether to disable warnings introduces a
dependency on the header inclusion order and thus can prevent the
warnings from being enabled.
Fixes #1173
Change-Id: I21f5bca78a83bfe4642e9b01abd220b9fbba31a4
diff --git a/include/ceres/internal/disable_warnings.h b/include/ceres/internal/disable_warnings.h
index b6e38aa..408698b 100644
--- a/include/ceres/internal/disable_warnings.h
+++ b/include/ceres/internal/disable_warnings.h
@@ -1,5 +1,5 @@
// Ceres Solver - A fast non-linear least squares minimizer
-// Copyright 2023 Google Inc. All rights reserved.
+// Copyright 2025 Google Inc. All rights reserved.
// http://ceres-solver.org/
//
// Redistribution and use in source and binary forms, with or without
@@ -28,10 +28,8 @@
//
// This file has the sole purpose to silence warnings when including Ceres.
-// This is not your usual header guard. The macro CERES_WARNINGS_DISABLED
-// shows up again in reenable_warnings.h.
-#ifndef CERES_WARNINGS_DISABLED
-#define CERES_WARNINGS_DISABLED
+// NOTE: An include guard is not necessary and in fact counterproductive because
+// #pragma warning(push) will depend on the inclusion order.
#ifdef _MSC_VER
#pragma warning(push)
@@ -40,5 +38,3 @@
// "if you are deriving from a type in the Standard C++ Library"
#pragma warning(disable : 4251)
#endif
-
-#endif // CERES_WARNINGS_DISABLED
diff --git a/include/ceres/internal/reenable_warnings.h b/include/ceres/internal/reenable_warnings.h
index a183c25..947cdfd 100644
--- a/include/ceres/internal/reenable_warnings.h
+++ b/include/ceres/internal/reenable_warnings.h
@@ -1,5 +1,5 @@
// Ceres Solver - A fast non-linear least squares minimizer
-// Copyright 2023 Google Inc. All rights reserved.
+// Copyright 2025 Google Inc. All rights reserved.
// http://ceres-solver.org/
//
// Redistribution and use in source and binary forms, with or without
@@ -27,12 +27,6 @@
// POSSIBILITY OF SUCH DAMAGE.
//
-// This is not your usual header guard. See disable_warnings.h
-#ifdef CERES_WARNINGS_DISABLED
-#undef CERES_WARNINGS_DISABLED
-
#ifdef _MSC_VER
#pragma warning(pop)
#endif
-
-#endif // CERES_WARNINGS_DISABLED
