diff --git a/include/exiv2/futils.hpp b/include/exiv2/futils.hpp
index 4d7963ef..3117fa81 100644
--- a/include/exiv2/futils.hpp
+++ b/include/exiv2/futils.hpp
@@ -59,11 +59,11 @@ namespace Exiv2
     // free functions
     /*!
       @brief  Return the value of environmental variable.
-      @param  var The name of environmental variable.
+      @param[in]  var The name of environmental variable. Must be a member of the enumeration @ref EnVar.
       @return the value of environmental variable. If it's empty, the default value is returned.
       @throws std::out_of_range when an unexpected EnVar is given as input.
      */
-    EXIV2API std::string getEnv(EnVar var);
+    EXIV2API std::string getEnv(int env_var);
 
     /*!
       @brief Encode the input url.
@@ -204,4 +204,4 @@ namespace Exiv2
 
 }  // namespace Exiv2
 
-#endif // #ifndef FUTILS_HPP_
\ No newline at end of file
+#endif // #ifndef FUTILS_HPP_
diff --git a/src/futils.cpp b/src/futils.cpp
index f2695132..d0d2c067 100644
--- a/src/futils.cpp
+++ b/src/futils.cpp
@@ -60,12 +60,13 @@ namespace Exiv2 {
     const char* ENVARKEY[] = {"EXIV2_HTTP_POST", "EXIV2_TIMEOUT"}; //!< @brief request keys for http exiv2 handler and time-out
 // *****************************************************************************
 // free functions
-    std::string getEnv(EnVar var)
+    std::string getEnv(int env_var)
     {
-        if (var < envHTTPPOST || var > envTIMEOUT) {
+        // this check is relying on undefined behavior and might not be effective
+        if (env_var < envHTTPPOST || env_var > envTIMEOUT) {
             throw std::out_of_range("Unexpected env variable");
         }
-        return getenv(ENVARKEY[var]) ? getenv(ENVARKEY[var]) : ENVARDEF[var];
+        return getenv(ENVARKEY[env_var]) ? getenv(ENVARKEY[env_var]) : ENVARDEF[env_var];
     }
 
     /// @brief Convert an integer value to its hex character.