gcc/ChangeLog:
* Makefile.in (USER_H): Add <stdcountof.h>.
* ginclude/stdcountof.h: Add countof macro.
gcc/testsuite/ChangeLog:
* gcc.dg/countof-stdcountof.c: Add tests for <stdcountof.h>.
Signed-off-by: Alejandro Colomar <a...@kernel.org>
---
gcc/Makefile.in | 1 +
gcc/ginclude/stdcountof.h | 31 +++++++++++++++++++++++
gcc/testsuite/gcc.dg/countof-stdcountof.c | 25 ++++++++++++++++++
3 files changed, 57 insertions(+)
create mode 100644 gcc/ginclude/stdcountof.h
create mode 100644 gcc/testsuite/gcc.dg/countof-stdcountof.c
diff --git a/gcc/Makefile.in b/gcc/Makefile.in
index 72d132207c0..fc8a7e532b9 100644
--- a/gcc/Makefile.in
+++ b/gcc/Makefile.in
@@ -481,6 +481,7 @@ USER_H = $(srcdir)/ginclude/float.h \
$(srcdir)/ginclude/stdalign.h \
$(srcdir)/ginclude/stdatomic.h \
$(srcdir)/ginclude/stdckdint.h \
+ $(srcdir)/ginclude/stdcountof.h \
$(EXTRA_HEADERS)
USER_H_INC_NEXT_PRE = @user_headers_inc_next_pre@
diff --git a/gcc/ginclude/stdcountof.h b/gcc/ginclude/stdcountof.h
new file mode 100644
index 00000000000..1d914f40e5d
--- /dev/null
+++ b/gcc/ginclude/stdcountof.h
@@ -0,0 +1,31 @@
+/* Copyright (C) 2025 Free Software Foundation, Inc.
+
+This file is part of GCC.
+
+GCC 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, or (at your option)
+any later version.
+
+GCC 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.
+
+Under Section 7 of GPL version 3, you are granted additional
+permissions described in the GCC Runtime Library Exception, version
+3.1, as published by the Free Software Foundation.
+
+You should have received a copy of the GNU General Public License and
+a copy of the GCC Runtime Library Exception along with this program;
+see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
+<http://www.gnu.org/licenses/>. */
+
+/* ISO C2Y: 7.21 Array count <stdcountof.h>. */
+
+#ifndef _STDCOUNTOF_H
+#define _STDCOUNTOF_H
+
+#define countof _Countof
+
+#endif /* stdcountof.h */
diff --git a/gcc/testsuite/gcc.dg/countof-stdcountof.c
b/gcc/testsuite/gcc.dg/countof-stdcountof.c
new file mode 100644
index 00000000000..a7fe4079c69
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/countof-stdcountof.c
@@ -0,0 +1,25 @@
+/* { dg-do run } */
+/* { dg-options "-std=c2y -pedantic-errors" } */
+
+#include <stdcountof.h>
+
+#undef NDEBUG
+#include <assert.h>
+
+extern int strcmp (const char *, const char *);
+
+#ifndef countof
+#error "countof not defined"
+#endif
+
+int a[3];
+int b[countof a];
+
+#define str(x) #x
+#define xstr(x) str(x)
+
+int
+main (void)
+{
+ assert (strcmp (xstr(countof), "_Countof") == 0);
+}
--
2.49.0
