1 files changed, 60 insertions, 0 deletions
diff --git a/src/warning.h b/src/warning.h
new file mode 100644
index 00000000..778ee407
--- /dev/null
+++ b/src/warning.h
@@ -0,0 +1,60 @@
+/* Control warning output in GNU Make.
+Copyright (C) 2023 Free Software Foundation, Inc.
+This file is part of GNU Make.
+
+GNU Make is free software; you can redistribute it and/or modify it under the
+terms of the GNU General Public License as published by the Free Software
+Foundation; either version 3 of the License, or (at your option) any later
+version.
+
+GNU Make is distributed in the hope that it will be useful, but WITHOUT ANY
+WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License along with
+this program.  If not, see <https://www.gnu.org/licenses/>.  */
+
+/* Types of warnings we can show.  */
+enum warning_type
+  {
+    wt_undefined_var = 0, /* Reference an undefined variable name.  */
+    wt_max
+  };
+
+/* State of a given warning.  */
+enum warning_state
+  {
+    w_unset = 0,
+    w_ignore,
+    w_warn,
+    w_error
+  };
+
+/* The default state of warnings.  */
+extern enum warning_state default_warnings[wt_max];
+
+/* Current state of warnings.  */
+extern enum warning_state warnings[wt_max];
+
+/* Global warning settings.  */
+extern enum warning_state warn_global;
+
+/* Get the current state of a given warning.  */
+#define warn_get(_w) (warnings[_w] != w_unset ? warnings[_w] \
+                      : warn_global != w_unset ? warn_global \
+                      : default_warnings[_w])
+
+/* Set the current state of a given warning.  Can't use w_unset here.  */
+#define warn_set(_w,_f) do{ warnings[_w] = (_f); } while (0)
+
+/* True if we should check for the warning in the first place.  */
+#define warn_check(_w)  (warn_get (_w) > w_ignore)
+
+/* Check if the warning is ignored.  */
+#define warn_ignored(_w) (warn_get (_w) == w_ignore)
+
+/* Check if the warning is in "warn" mode.  */
+#define warn_warned(_w)  (warn_get (_w) == w_warn)
+
+/* Check if the warning is in "error" mode.  */
+#define warn_error(_w)   (warn_get (_w) == w_error)