diff --git a/include/spdlog/details/os-inl.h b/include/spdlog/details/os-inl.h
index a7cd37f7..5f082e57 100644
--- a/include/spdlog/details/os-inl.h
+++ b/include/spdlog/details/os-inl.h
@@ -542,7 +542,7 @@ static SPDLOG_INLINE bool mkdir_(const filename_t &path)
 
 // create the given directory - and all directories leading to it
 // return true on success or if the directory already exists
-SPDLOG_INLINE bool create_dir(filename_t path)
+SPDLOG_INLINE bool create_dir(const filename_t &path)
 {
     if (path_exists(path))
     {
@@ -581,7 +581,7 @@ SPDLOG_INLINE bool create_dir(filename_t path)
 // "abc/" => "abc"
 // "abc" => ""
 // "abc///" => "abc//"
-SPDLOG_INLINE filename_t dir_name(filename_t path)
+SPDLOG_INLINE filename_t dir_name(const filename_t &path)
 {
     auto pos = path.find_last_of(folder_seps_filename);
     return pos != filename_t::npos ? path.substr(0, pos) : filename_t{};
diff --git a/include/spdlog/details/os.h b/include/spdlog/details/os.h
index 2b2ffa1d..b154bc47 100644
--- a/include/spdlog/details/os.h
+++ b/include/spdlog/details/os.h
@@ -99,11 +99,11 @@ SPDLOG_API void utf8_to_wstrbuf(string_view_t str, wmemory_buf_t &target);
 // "abc/" => "abc"
 // "abc" => ""
 // "abc///" => "abc//"
-SPDLOG_API filename_t dir_name(filename_t path);
+SPDLOG_API filename_t dir_name(const filename_t &path);
 
 // Create a dir from the given path.
 // Return true if succeeded or if this dir already exists.
-SPDLOG_API bool create_dir(filename_t path);
+SPDLOG_API bool create_dir(const filename_t &path);
 
 // non thread safe, cross platform getenv/getenv_s
 // return empty string if field not found
diff --git a/include/spdlog/pattern_formatter.h b/include/spdlog/pattern_formatter.h
index 147d8546..6810f03b 100644
--- a/include/spdlog/pattern_formatter.h
+++ b/include/spdlog/pattern_formatter.h
@@ -68,7 +68,7 @@ class SPDLOG_API custom_flag_formatter : public details::flag_formatter
 public:
     virtual std::unique_ptr<custom_flag_formatter> clone() const = 0;
 
-    void set_padding_info(details::padding_info padding)
+    void set_padding_info(const details::padding_info& padding)
     {
         flag_formatter::padinfo_ = padding;
     }