diff --git a/include/maxscale/cdefs.h b/include/maxscale/cdefs.h
index 89819b78a..13c6e8e6e 100644
--- a/include/maxscale/cdefs.h
+++ b/include/maxscale/cdefs.h
@@ -79,6 +79,17 @@
  */
 #define MXS_MAX(a,b) ((a)>(b) ? (a) : (b))
 
+/**
+ * Define function attributes
+ *
+ * The function attributes are compiler specific.
+ */
+#ifdef __GNUC__
+#define mxs_attribute(a) __attribute__(a)
+#else
+#define mxs_attribute(a)
+#endif
+
 /**
  * COMMON INCLUDE FILES
  */
diff --git a/include/maxscale/log_manager.h b/include/maxscale/log_manager.h
index e926599a0..e1452d7d4 100644
--- a/include/maxscale/log_manager.h
+++ b/include/maxscale/log_manager.h
@@ -119,7 +119,7 @@ static inline bool mxs_log_priority_is_enabled(int priority)
 int mxs_log_message(int priority,
                     const char* modname,
                     const char* file, int line, const char* function,
-                    const char* format, ...) __attribute__((format(printf, 6, 7)));
+                    const char* format, ...) mxs_attribute((format(printf, 6, 7)));
 /**
  * Log an error, warning, notice, info, or debug  message.
  *
diff --git a/include/maxscale/modulecmd.h b/include/maxscale/modulecmd.h
index bcbb3d5ff..427208484 100644
--- a/include/maxscale/modulecmd.h
+++ b/include/maxscale/modulecmd.h
@@ -256,7 +256,7 @@ bool modulecmd_call_command(const MODULECMD *cmd, const MODULECMD_ARG *args, jso
  * @param format Format string
  * @param ... Format string arguments
  */
-void modulecmd_set_error(const char *format, ...);
+void modulecmd_set_error(const char *format, ...) mxs_attribute((format (printf, 1, 2)));
 
 /**
  * @brief Get the latest error generated by the modulecmd system
diff --git a/server/core/config_runtime.cc b/server/core/config_runtime.cc
index 846af16c2..9559c078e 100644
--- a/server/core/config_runtime.cc
+++ b/server/core/config_runtime.cc
@@ -42,6 +42,9 @@ static SPINLOCK crt_lock = SPINLOCK_INIT;
 #define RUNTIME_ERRMSG_BUFSIZE 512
 thread_local char runtime_errmsg[RUNTIME_ERRMSG_BUFSIZE];
 
+/** Attributes need to be in the declaration */
+static void runtime_error(const char* fmt, ...) mxs_attribute((format (printf, 1, 2)));
+
 static void runtime_error(const char* fmt, ...)
 {
     va_list list;
@@ -1166,7 +1169,8 @@ static bool validate_ssl_json(json_t* params)
             !mxs_json_pointer(params, CN_SSL_CERT) ||
             !mxs_json_pointer(params, CN_SSL_CA_CERT))
         {
-            runtime_error("SSL configuration requires '%s', '%s' and '%s' parameters");
+            runtime_error("SSL configuration requires '%s', '%s' and '%s' parameters",
+                          CN_SSL_KEY, CN_SSL_CERT, CN_SSL_CA_CERT);
             rval = false;
         }
 
diff --git a/server/core/modulecmd.cc b/server/core/modulecmd.cc
index 7849de63a..6d2b4f615 100644
--- a/server/core/modulecmd.cc
+++ b/server/core/modulecmd.cc
@@ -509,7 +509,7 @@ MODULECMD_ARG* modulecmd_arg_parse(const MODULECMD *cmd, int argc, const void **
                 if (!process_argument(cmd, &cmd->arg_types[i], argv[i], &arg->argv[i], &err))
                 {
                     error = true;
-                    modulecmd_set_error("Argument %d, %s: %s", i + 1, err, argv[i] ? argv[i] : "No argument given");
+                    modulecmd_set_error("Argument %d, %s: %s", i + 1, err, argv[i] ? (char*)argv[i] : "No argument given");
                     break;
                 }
             }