From 13038f37e87efa44e2a1409f41da1fa7c02fee7d Mon Sep 17 00:00:00 2001
From: Justin Riddell <arghnews@hotmail.co.uk>
Date: Wed, 10 Jul 2024 16:35:06 +0100
Subject: [PATCH] Support printing (const) volatile void* (#4056)

Fixes #4049
---
 include/fmt/base.h | 6 ++++++
 test/base-test.cc  | 8 ++++++++
 2 files changed, 14 insertions(+)

diff --git a/include/fmt/base.h b/include/fmt/base.h
index ceb9845591eb..c95ca6a48ca7 100644
--- a/include/fmt/base.h
+++ b/include/fmt/base.h
@@ -1476,6 +1476,12 @@ template <typename Context> struct arg_mapper {
 
   FMT_MAP_API auto map(void* val) -> const void* { return val; }
   FMT_MAP_API auto map(const void* val) -> const void* { return val; }
+  FMT_MAP_API auto map(volatile void* val) -> const void* {
+    return const_cast<const void*>(val);
+  }
+  FMT_MAP_API auto map(const volatile void* val) -> const void* {
+    return const_cast<const void*>(val);
+  }
   FMT_MAP_API auto map(std::nullptr_t val) -> const void* { return val; }
 
   // Use SFINAE instead of a const T* parameter to avoid a conflict with the
diff --git a/test/base-test.cc b/test/base-test.cc
index c82e7378cd94..7f0a6abfd669 100644
--- a/test/base-test.cc
+++ b/test/base-test.cc
@@ -425,6 +425,14 @@ TEST(arg_test, pointer_arg) {
   CHECK_ARG_SIMPLE(cp);
 }
 
+TEST(arg_test, volatile_pointer_arg) {
+  const void* p = nullptr;
+  volatile int* vip = nullptr;
+  const volatile int* cvip = nullptr;
+  CHECK_ARG(char, p, static_cast<volatile void*>(vip));
+  CHECK_ARG(char, p, static_cast<const volatile void*>(cvip));
+}
+
 struct check_custom {
   auto operator()(fmt::basic_format_arg<fmt::format_context>::handle h) const
       -> test_result {