From cc5e38fa5c356c8593f7f592649a353bed9154ed Mon Sep 17 00:00:00 2001
From: Justin Riddell <arghnews@hotmail.co.uk>
Date: Tue, 9 Jul 2024 21:04:08 +0100
Subject: [PATCH] Support printing (const) volatile void*

Fixes #4049
---
 include/fmt/base.h | 6 ++++++
 test/base-test.cc  | 9 +++++++++
 2 files changed, 15 insertions(+)

diff --git a/include/fmt/base.h b/include/fmt/base.h
index ceb9845591ebe..c95ca6a48ca73 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 c82e7378cd94d..703728f7b5ab2 100644
--- a/test/base-test.cc
+++ b/test/base-test.cc
@@ -425,6 +425,15 @@ TEST(arg_test, pointer_arg) {
   CHECK_ARG_SIMPLE(cp);
 }
 
+TEST(arg_test, volatile_pointer_arg) {
+  int val = 0;
+  CHECK_ARG(char, reinterpret_cast<const void*>(val),
+            static_cast<volatile void*>(reinterpret_cast<volatile int*>(val)));
+  CHECK_ARG(char, reinterpret_cast<const void*>(val),
+            static_cast<const volatile void*>(
+                reinterpret_cast<const volatile int*>(val)));
+}
+
 struct check_custom {
   auto operator()(fmt::basic_format_arg<fmt::format_context>::handle h) const
       -> test_result {