diff --git a/srtcore/api.cpp b/srtcore/api.cpp
index b1837b176..42452051b 100644
--- a/srtcore/api.cpp
+++ b/srtcore/api.cpp
@@ -2005,7 +2005,7 @@ SRTSOCKET CUDT::socket(int af, int, int)
       s_UDTUnited.setError(new CUDTException(e));
       return INVALID_SOCK;
    }
-   catch (bad_alloc)
+   catch (bad_alloc&)
    {
       s_UDTUnited.setError(new CUDTException(MJ_SYSTEMRES, MN_MEMORY, 0));
       return INVALID_SOCK;
@@ -2031,7 +2031,7 @@ int CUDT::bind(SRTSOCKET u, const sockaddr* name, int namelen)
       s_UDTUnited.setError(new CUDTException(e));
       return ERROR;
    }
-   catch (bad_alloc)
+   catch (bad_alloc&)
    {
       s_UDTUnited.setError(new CUDTException(MJ_SYSTEMRES, MN_MEMORY, 0));
       return ERROR;
@@ -2057,7 +2057,7 @@ int CUDT::bind(SRTSOCKET u, UDPSOCKET udpsock)
       s_UDTUnited.setError(new CUDTException(e));
       return ERROR;
    }
-   catch (bad_alloc)
+   catch (bad_alloc&)
    {
       s_UDTUnited.setError(new CUDTException(MJ_SYSTEMRES, MN_MEMORY, 0));
       return ERROR;
@@ -2082,7 +2082,7 @@ int CUDT::listen(SRTSOCKET u, int backlog)
       s_UDTUnited.setError(new CUDTException(e));
       return ERROR;
    }
-   catch (bad_alloc)
+   catch (bad_alloc&)
    {
       s_UDTUnited.setError(new CUDTException(MJ_SYSTEMRES, MN_MEMORY, 0));
       return ERROR;
@@ -2128,7 +2128,7 @@ int CUDT::connect(
       s_UDTUnited.setError(new CUDTException(e));
       return ERROR;
    }
-   catch (bad_alloc)
+   catch (bad_alloc&)
    {
       s_UDTUnited.setError(new CUDTException(MJ_SYSTEMRES, MN_MEMORY, 0));
       return ERROR;
@@ -2259,7 +2259,7 @@ int CUDT::send(SRTSOCKET u, const char* buf, int len, int)
       s_UDTUnited.setError(new CUDTException(e));
       return ERROR;
    }
-   catch (bad_alloc)
+   catch (bad_alloc&)
    {
       s_UDTUnited.setError(new CUDTException(MJ_SYSTEMRES, MN_MEMORY, 0));
       return ERROR;
@@ -2308,7 +2308,7 @@ int CUDT::sendmsg(
       s_UDTUnited.setError(new CUDTException(e));
       return ERROR;
    }
-   catch (bad_alloc)
+   catch (bad_alloc&)
    {
       s_UDTUnited.setError(new CUDTException(MJ_SYSTEMRES, MN_MEMORY, 0));
       return ERROR;
@@ -2335,7 +2335,7 @@ int CUDT::sendmsg2(
       s_UDTUnited.setError(new CUDTException(e));
       return ERROR;
    }
-   catch (bad_alloc)
+   catch (bad_alloc&)
    {
       s_UDTUnited.setError(new CUDTException(MJ_SYSTEMRES, MN_MEMORY, 0));
       return ERROR;
@@ -2403,7 +2403,7 @@ int64_t CUDT::sendfile(
       s_UDTUnited.setError(new CUDTException(e));
       return ERROR;
    }
-   catch (bad_alloc)
+   catch (bad_alloc&)
    {
       s_UDTUnited.setError(new CUDTException(MJ_SYSTEMRES, MN_MEMORY, 0));
       return ERROR;
@@ -2461,7 +2461,7 @@ int CUDT::select(
       s_UDTUnited.setError(new CUDTException(e));
       return ERROR;
    }
-   catch (bad_alloc)
+   catch (bad_alloc&)
    {
       s_UDTUnited.setError(new CUDTException(MJ_SYSTEMRES, MN_MEMORY, 0));
       return ERROR;
@@ -2497,7 +2497,7 @@ int CUDT::selectEx(
       s_UDTUnited.setError(new CUDTException(e));
       return ERROR;
    }
-   catch (bad_alloc)
+   catch (bad_alloc&)
    {
       s_UDTUnited.setError(new CUDTException(MJ_SYSTEMRES, MN_MEMORY, 0));
       return ERROR;
diff --git a/srtcore/utilities.h b/srtcore/utilities.h
index ee8cfda69..d323a1651 100755
--- a/srtcore/utilities.h
+++ b/srtcore/utilities.h
@@ -68,12 +68,13 @@ written by
 #define ATR_OVERRIDE
 #define ATR_FINAL
 
-#if defined(REQUIRE_CXX11) && REQUIRE_CXX11 == 1
-#error "The currently compiled application required C++11, but your compiler doesn't support it."
 #endif
 
+#if !HAVE_CXX11 && defined(REQUIRE_CXX11) && REQUIRE_CXX11 == 1
+#error "The currently compiled application required C++11, but your compiler doesn't support it."
 #endif
 
+
 // Windows warning disabler
 #define _CRT_SECURE_NO_WARNINGS 1
 
@@ -91,6 +92,11 @@ written by
 #include <memory>
 #include <sstream>
 #include <iomanip>
+
+#if HAVE_CXX11
+#include <type_traits>
+#endif
+
 #include <cstdlib>
 #include <cerrno>
 #include <cstring>
@@ -681,7 +687,17 @@ struct CallbackHolder
     {
         // Test if the pointer is a pointer to function. Don't let
         // other type of pointers here.
+#if HAVE_CXX11
+        static_assert(std::is_function<Signature>::value, "CallbackHolder is for functions only!");
+#else
+        // This is a poor-man's replacement, which should in most compilers
+        // generate a warning, if `Signature` resolves to a value type.
+        // This would make an illegal pointer cast from a value to a function type.
+        // Casting function-to-function, however, should not. Unfortunately
+        // newer compilers disallow that, too (when a signature differs), but
+        // then they should better use the C++11 way, much more reliable and safer.
         void* (*testfn)(void*) ATR_UNUSED = (void*(*)(void*))f;
+#endif
         opaque = o;
         fn = f;
     }