diff --git a/third-party/pmr/monolithic.hpp b/third-party/pmr/monolithic.hpp
index 8210ecc..a7d1cc6 100644
--- a/third-party/pmr/monolithic.hpp
+++ b/third-party/pmr/monolithic.hpp
@@ -5,8 +5,8 @@
  *          http://www.boost.org/LICENSE_1_0.txt)
  */
 
-#ifndef PMR__MONOLITHIC_HPP__
-#define PMR__MONOLITHIC_HPP__
+#ifndef PMR_MONOLITHIC_HPP_
+#define PMR_MONOLITHIC_HPP_
 
 #include "pmr_vector.hpp"
 #include "polymorphic_allocator.hpp"
@@ -111,4 +111,4 @@ monolithic::do_is_equal(const memory_resource &other) const noexcept
 
 } // close namespace cpp17
 
-#endif // PMR__MONOLITHIC_HPP__
+#endif // PMR_MONOLITHIC_HPP_
diff --git a/third-party/pmr/pmr_deque.hpp b/third-party/pmr/pmr_deque.hpp
index f8a8639..d43e4e2 100644
--- a/third-party/pmr/pmr_deque.hpp
+++ b/third-party/pmr/pmr_deque.hpp
@@ -5,8 +5,8 @@
  *          http://www.boost.org/LICENSE_1_0.txt)
  */
 
-#ifndef PMR__PMR_DEQUE_HPP__
-#define PMR__PMR_DEQUE_HPP__
+#ifndef PMR_PMR_DEQUE_HPP_
+#define PMR_PMR_DEQUE_HPP_
 
 #include <deque>
 
@@ -22,4 +22,4 @@ namespace pmr {
 }
 }
 
-#endif // PMR__PMR_DEQUE_HPP__
+#endif // PMR_PMR_DEQUE_HPP_
diff --git a/third-party/pmr/pmr_string.hpp b/third-party/pmr/pmr_string.hpp
index 7e11a2b..6dde28f 100644
--- a/third-party/pmr/pmr_string.hpp
+++ b/third-party/pmr/pmr_string.hpp
@@ -5,8 +5,8 @@
  *          http://www.boost.org/LICENSE_1_0.txt)
  */
 
-#ifndef PMR__PMR_STRING_HPP__
-#define PMR__PMR_STRING_HPP__
+#ifndef PMR_PMR_STRING_HPP_
+#define PMR_PMR_STRING_HPP_
 
 #include <type_traits>
 #include <string>
@@ -142,4 +142,4 @@ namespace pmr {
 } // Close namespace pmr
 } // Close namespace cpp17
 
-#endif // PMR__PMR_STRING_HPP__
+#endif // PMR_PMR_STRING_HPP_
diff --git a/third-party/pmr/pmr_vector.hpp b/third-party/pmr/pmr_vector.hpp
index 290ddd8..9acb26d 100644
--- a/third-party/pmr/pmr_vector.hpp
+++ b/third-party/pmr/pmr_vector.hpp
@@ -5,8 +5,8 @@
  *          http://www.boost.org/LICENSE_1_0.txt)
  */
 
-#ifndef PMR__PMR_VECTOR_HPP__
-#define PMR__PMR_VECTOR_HPP__
+#ifndef PMR_PMR_VECTOR_HPP_
+#define PMR_PMR_VECTOR_HPP_
 
 #include <vector>
 
@@ -22,4 +22,4 @@ namespace pmr {
 }
 }
 
-#endif // PMR__PMR_VECTOR_HPP__
+#endif // PMR_PMR_VECTOR_HPP_
diff --git a/third-party/pmr/polymorphic_allocator.hpp b/third-party/pmr/polymorphic_allocator.hpp
index 7daee13..caeb6f3 100644
--- a/third-party/pmr/polymorphic_allocator.hpp
+++ b/third-party/pmr/polymorphic_allocator.hpp
@@ -5,8 +5,8 @@
  *          http://www.boost.org/LICENSE_1_0.txt)
  */
 
-#ifndef PMR__POLYMORPHIC_ALLOCATOR_HPP__
-#define PMR__POLYMORPHIC_ALLOCATOR_HPP__
+#ifndef PMR_POLYMORPHIC_ALLOCATOR_HPP_
+#define PMR_POLYMORPHIC_ALLOCATOR_HPP_
 
 #include <atomic>
 #include <memory>
@@ -474,4 +474,4 @@ bool __pmrd::operator!=(const __pmrd::polymorphic_allocator_imp<T1>& a,
 
 } // close namespace cpp17
 
-#endif // PMR__POLYMORPHIC_ALLOCATOR_HPP__
+#endif // PMR_POLYMORPHIC_ALLOCATOR_HPP_