diff --git a/include/spdlog/sinks/ansicolor_sink.h b/include/spdlog/sinks/ansicolor_sink.h
index 9e7f1a59..db12cffe 100644
--- a/include/spdlog/sinks/ansicolor_sink.h
+++ b/include/spdlog/sinks/ansicolor_sink.h
@@ -31,9 +31,9 @@ public:
         colors_[level::trace] = cyan;
         colors_[level::debug] = cyan;
         colors_[level::info] = reset;
-        colors_[level::warn] = yellow + bold;
-        colors_[level::err] = red + bold;
-        colors_[level::critical] = bold + on_red;
+        colors_[level::warn] = string(yellow) + bold;
+        colors_[level::err] = string(red) + bold;
+        colors_[level::critical] = string(bold) + on_red;
         colors_[level::off] = reset;
     }
 
@@ -42,41 +42,41 @@ public:
         _flush();
     }
 
-    void set_color(level::level_enum color_level, const std::string &color)
+    void set_color(level::level_enum color_level, const string &color)
     {
         std::lock_guard<Mutex> lock(base_sink<Mutex>::_mutex);
         colors_[color_level] = color;
     }
 
     /// Formatting codes
-    const std::string reset = "\033[m";
-    const std::string bold = "\033[1m";
-    const std::string dark = "\033[2m";
-    const std::string underline = "\033[4m";
-    const std::string blink = "\033[5m";
-    const std::string reverse = "\033[7m";
-    const std::string concealed = "\033[8m";
-    const std::string clear_line = "\033[K";
+    const char* reset = "\033[m";
+    const char* bold = "\033[1m";
+    const char* dark = "\033[2m";
+    const char* underline = "\033[4m";
+    const char* blink = "\033[5m";
+    const char* reverse = "\033[7m";
+    const char* concealed = "\033[8m";
+    const char* clear_line = "\033[K";
 
     // Foreground colors
-    const std::string black = "\033[30m";
-    const std::string red = "\033[31m";
-    const std::string green = "\033[32m";
-    const std::string yellow = "\033[33m";
-    const std::string blue = "\033[34m";
-    const std::string magenta = "\033[35m";
-    const std::string cyan = "\033[36m";
-    const std::string white = "\033[37m";
+    const char* black = "\033[30m";
+    const char* red = "\033[31m";
+    const char* green = "\033[32m";
+    const char* yellow = "\033[33m";
+    const char* blue = "\033[34m";
+    const char* magenta = "\033[35m";
+    const char* cyan = "\033[36m";
+    const char* white = "\033[37m";
 
     /// Background colors
-    const std::string on_black = "\033[40m";
-    const std::string on_red = "\033[41m";
-    const std::string on_green = "\033[42m";
-    const std::string on_yellow = "\033[43m";
-    const std::string on_blue = "\033[44m";
-    const std::string on_magenta = "\033[45m";
-    const std::string on_cyan = "\033[46m";
-    const std::string on_white = "\033[47m";
+    const char* on_black = "\033[40m";
+    const char* on_red = "\033[41m";
+    const char* on_green = "\033[42m";
+    const char* on_yellow = "\033[43m";
+    const char* on_blue = "\033[44m";
+    const char* on_magenta = "\033[45m";
+    const char* on_cyan = "\033[46m";
+    const char* on_white = "\033[47m";
 
 protected:
     void _sink_it(const details::log_msg &msg) override
@@ -85,7 +85,7 @@ protected:
         // If color is not supported in the terminal, log as is instead.
         if (should_do_colors_)
         {
-            const std::string &prefix = colors_[msg.level];
+            const string& prefix = colors_[msg.level];
             fwrite(prefix.data(), sizeof(char), prefix.size(), target_file_);
             fwrite(msg.formatted.data(), sizeof(char), msg.formatted.size(), target_file_);
             fwrite(reset.data(), sizeof(char), reset.size(), target_file_);
@@ -105,7 +105,7 @@ protected:
 
     FILE *target_file_;
     bool should_do_colors_;
-    std::unordered_map<level::level_enum, std::string, level::level_hasher> colors_;
+    unordered_map<level::level_enum, string, level::level_hasher> colors_;
 };
 
 template<class Mutex>