diff --git a/CMakeLists.txt b/CMakeLists.txt
index 4106204..2677753 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -21,7 +21,7 @@ else ()
     message(STATUS "Compiler is recent enough to support C++17.")
 endif ()
 
-set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++1z -pthread -Wall")
+set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=c++17 -pthread -Wall")
 set(CMAKE_CXX_FLAGS_RELEASE "${CMAKE_CXX_FLAGS_RELEASE} -DNDEBUG -march=native -O3")
 set(CMAKE_CXX_FLAGS_DEBUG "${CMAKE_CXX_FLAGS_DEBUG} -fsanitize=address -fno-omit-frame-pointer -O0 -g -DDEBUG")
 
diff --git a/include/xcdat.hpp b/include/xcdat.hpp
index 22a7823..de8085b 100644
--- a/include/xcdat.hpp
+++ b/include/xcdat.hpp
@@ -1,5 +1,8 @@
 #pragma once
 
+#include <fstream>
+#include <string>
+
 #include "xcdat/bc_vector_15.hpp"
 #include "xcdat/bc_vector_16.hpp"
 #include "xcdat/bc_vector_7.hpp"
@@ -40,7 +43,7 @@ template <class Trie>
 
 //! Load the trie dictionary from the file.
 template <class Trie>
-[[maybe_unused]] Trie load(std::string_view filepath) {
+[[maybe_unused]] Trie load(const std::string& filepath) {
     load_visitor visitor(filepath);
 
     std::uint32_t flag;
@@ -54,7 +57,7 @@ template <class Trie>
 
 //! Save the trie dictionary to the file and returns the file size in bytes.
 template <class Trie>
-[[maybe_unused]] std::uint64_t save(const Trie& idx, std::string_view filepath) {
+[[maybe_unused]] std::uint64_t save(const Trie& idx, const std::string& filepath) {
     save_visitor visitor(filepath);
     visitor.visit(static_cast<std::uint32_t>(Trie::l1_bits));  // flag
     visitor.visit(const_cast<Trie&>(idx));
@@ -72,7 +75,7 @@ template <class Trie>
 
 //! Get the flag indicating the trie dictionary type, embedded by the function 'save'.
 //! The flag corresponds to trie::l1_bits and will be used to detect the trie type from the file.
-[[maybe_unused]] std::uint32_t get_flag(std::string_view filepath) {
+[[maybe_unused]] std::uint32_t get_flag(const std::string& filepath) {
     std::ifstream ifs(filepath);
     XCDAT_THROW_IF(!ifs.good(), "Cannot open the input file");
 
@@ -82,7 +85,7 @@ template <class Trie>
 }
 
 //! Load the keywords from the file.
-[[maybe_unused]] std::vector<std::string> load_strings(std::string_view filepath, char delim = '\n') {
+[[maybe_unused]] std::vector<std::string> load_strings(const std::string& filepath, char delim = '\n') {
     std::ifstream ifs(filepath);
     XCDAT_THROW_IF(!ifs.good(), "Cannot open the input file");
 
diff --git a/include/xcdat/load_visitor.hpp b/include/xcdat/load_visitor.hpp
index bf6cf66..8c9488c 100644
--- a/include/xcdat/load_visitor.hpp
+++ b/include/xcdat/load_visitor.hpp
@@ -1,6 +1,6 @@
 #pragma once
 
-#include <string_view>
+#include <string>
 #include <type_traits>
 
 #include "exception.hpp"
@@ -13,7 +13,7 @@ class load_visitor {
     std::ifstream m_ifs;
 
   public:
-    load_visitor(std::string_view filepath) : m_ifs(filepath, std::ios::binary) {
+    load_visitor(const std::string& filepath) : m_ifs(filepath, std::ios::binary) {
         XCDAT_THROW_IF(!m_ifs.good(), "Cannot open the input file");
     }
 
diff --git a/include/xcdat/save_visitor.hpp b/include/xcdat/save_visitor.hpp
index f81270b..5b0e489 100644
--- a/include/xcdat/save_visitor.hpp
+++ b/include/xcdat/save_visitor.hpp
@@ -1,6 +1,6 @@
 #pragma once
 
-#include <string_view>
+#include <string>
 #include <type_traits>
 
 #include "exception.hpp"
@@ -13,7 +13,7 @@ class save_visitor {
     std::ofstream m_ofs;
 
   public:
-    save_visitor(std::string_view filepath) : m_ofs(filepath, std::ios::binary) {
+    save_visitor(const std::string& filepath) : m_ofs(filepath, std::ios::binary) {
         XCDAT_THROW_IF(!m_ofs.good(), "Cannot open the input file");
     }