diff --git a/iceoryx_hoofs/include/iceoryx_hoofs/cxx/functional_interface.hpp b/iceoryx_hoofs/include/iceoryx_hoofs/cxx/functional_interface.hpp
index e67065b943..e7569626f6 100644
--- a/iceoryx_hoofs/include/iceoryx_hoofs/cxx/functional_interface.hpp
+++ b/iceoryx_hoofs/include/iceoryx_hoofs/cxx/functional_interface.hpp
@@ -18,8 +18,9 @@
 
 #include "iceoryx_hoofs/cxx/function_ref.hpp"
 #include "iceoryx_hoofs/cxx/type_traits.hpp"
+#include "iceoryx_hoofs/platform/unistd.hpp"
 
-#include <iostream>
+#include <cstring>
 #include <utility>
 
 namespace iox
diff --git a/iceoryx_hoofs/include/iceoryx_hoofs/internal/cxx/functional_interface.inl b/iceoryx_hoofs/include/iceoryx_hoofs/internal/cxx/functional_interface.inl
index cd0ce76e29..3e5967cc68 100644
--- a/iceoryx_hoofs/include/iceoryx_hoofs/internal/cxx/functional_interface.inl
+++ b/iceoryx_hoofs/include/iceoryx_hoofs/internal/cxx/functional_interface.inl
@@ -37,7 +37,9 @@ inline void Expect<Derived>::expect(const StringType& msg) const noexcept
 
     if (!(*static_cast<const Derived*>(this)))
     {
-        std::cout << msg << std::endl;
+        // it is possible that expect is called inside an error handler therefore we
+        // use write
+        IOX_DISCARD_RESULT(write(STDERR_FILENO, &msg[0], strlen(&msg[0])));
         Ensures(false);
     }
 }
@@ -53,7 +55,9 @@ inline ValueType& ExpectWithValue<Derived, ValueType>::expect(const StringType&
 
     if (!(*derivedThis))
     {
-        std::cout << msg << std::endl;
+        // it is possible that expect is called inside an error handler therefore we
+        // use write
+        IOX_DISCARD_RESULT(write(STDERR_FILENO, &msg[0], strlen(&msg[0])));
         Ensures(false);
     }