diff --git a/include/exiv2/error.hpp b/include/exiv2/error.hpp
index 6b7e18e408..b240624c04 100644
--- a/include/exiv2/error.hpp
+++ b/include/exiv2/error.hpp
@@ -292,7 +292,7 @@ class EXIV2API Error : public std::exception {
 };
 
 //! %Error output operator
-inline std::ostream& operator<<(std::ostream& os, const Error& error) {
+static std::ostream& operator<<(std::ostream& os, const Error& error) {
   return os << error.what();
 }
 
diff --git a/include/exiv2/metadatum.hpp b/include/exiv2/metadatum.hpp
index 33ffbc320d..8b0dd8c935 100644
--- a/include/exiv2/metadatum.hpp
+++ b/include/exiv2/metadatum.hpp
@@ -92,7 +92,7 @@ class EXIV2API Key {
 };  // class Key
 
 //! Output operator for Key types
-inline std::ostream& operator<<(std::ostream& os, const Key& key) {
+static std::ostream& operator<<(std::ostream& os, const Key& key) {
   return key.write(os);
 }
 
@@ -273,7 +273,7 @@ class EXIV2API Metadatum {
   @brief Output operator for Metadatum types, writing the interpreted
          tag value.
  */
-inline std::ostream& operator<<(std::ostream& os, const Metadatum& md) {
+static std::ostream& operator<<(std::ostream& os, const Metadatum& md) {
   return md.write(os);
 }
 
diff --git a/include/exiv2/slice.hpp b/include/exiv2/slice.hpp
index 9842ebcb0c..4bd882474d 100644
--- a/include/exiv2/slice.hpp
+++ b/include/exiv2/slice.hpp
@@ -17,7 +17,7 @@ namespace Internal {
  * knowledge about the stored data.
  */
 struct SliceBase {
-  inline SliceBase(size_t begin, size_t end) : begin_(begin), end_(end) {
+  SliceBase(size_t begin, size_t end) : begin_(begin), end_(end) {
     if (begin >= end) {
       throw std::out_of_range("Begin must be smaller than end");
     }
@@ -26,7 +26,7 @@ struct SliceBase {
   /*!
    * Return the number of elements in the slice.
    */
-  [[nodiscard]] inline size_t size() const noexcept {
+  [[nodiscard]] size_t size() const noexcept {
     // cannot underflow, as we know that begin < end
     return end_ - begin_;
   }
@@ -38,7 +38,7 @@ struct SliceBase {
    * @throw std::out_of_range when `index` will access an element
    * outside of the slice
    */
-  inline void rangeCheck(size_t index) const {
+  void rangeCheck(size_t index) const {
     if (index >= size()) {
       throw std::out_of_range("Index outside of the slice");
     }
@@ -530,24 +530,24 @@ struct Slice<T*> : public Internal::MutableSliceBase<Internal::PtrSliceStorage,
  * parameter deduction.
  */
 template <typename T>
-inline Slice<T> makeSlice(T& cont, size_t begin, size_t end) {
-  return Slice<T>(cont, begin, end);
+Slice<T> makeSlice(T& cont, size_t begin, size_t end) {
+  return {cont, begin, end};
 }
 
 /*!
  * Overload of makeSlice for slices of C-arrays.
  */
 template <typename T>
-inline Slice<T*> makeSlice(T* ptr, size_t begin, size_t end) {
-  return Slice<T*>(ptr, begin, end);
+Slice<T*> makeSlice(T* ptr, size_t begin, size_t end) {
+  return {ptr, begin, end};
 }
 
 /*!
  * @brief Return a new slice spanning the whole container.
  */
 template <typename container>
-inline Slice<container> makeSlice(container& cont) {
-  return Slice<container>(cont, 0, cont.size());
+Slice<container> makeSlice(container& cont) {
+  return {cont, 0, cont.size()};
 }
 
 /*!
@@ -555,24 +555,24 @@ inline Slice<container> makeSlice(container& cont) {
  * container.
  */
 template <typename container>
-inline Slice<container> makeSliceFrom(container& cont, size_t begin) {
-  return Slice<container>(cont, begin, cont.size());
+Slice<container> makeSliceFrom(container& cont, size_t begin) {
+  return {cont, begin, cont.size()};
 }
 
 /*!
  * @brief Return a new slice spanning until `end`.
  */
 template <typename container>
-inline Slice<container> makeSliceUntil(container& cont, size_t end) {
-  return Slice<container>(cont, 0, end);
+Slice<container> makeSliceUntil(container& cont, size_t end) {
+  return {cont, 0, end};
 }
 
 /*!
  * Overload of makeSliceUntil for pointer based slices.
  */
 template <typename T>
-inline Slice<T*> makeSliceUntil(T* ptr, size_t end) {
-  return Slice<T*>(ptr, 0, end);
+Slice<T*> makeSliceUntil(T* ptr, size_t end) {
+  return {ptr, 0, end};
 }
 
 }  // namespace Exiv2
diff --git a/include/exiv2/tags.hpp b/include/exiv2/tags.hpp
index 1eae8b0abd..dcf7c9f506 100644
--- a/include/exiv2/tags.hpp
+++ b/include/exiv2/tags.hpp
@@ -176,7 +176,7 @@ enum class IfdId : uint32_t {
   ignoreId = lastId
 };
 
-inline std::ostream& operator<<(std::ostream& os, IfdId id) {
+static std::ostream& operator<<(std::ostream& os, IfdId id) {
   return os << static_cast<int>(id);
 }
 
diff --git a/include/exiv2/value.hpp b/include/exiv2/value.hpp
index 0c55d822e0..86655e8997 100644
--- a/include/exiv2/value.hpp
+++ b/include/exiv2/value.hpp
@@ -239,7 +239,7 @@ class EXIV2API Value {
 };
 
 //! Output operator for Value types
-inline std::ostream& operator<<(std::ostream& os, const Value& value) {
+static std::ostream& operator<<(std::ostream& os, const Value& value) {
   return value.write(os);
 }