diff --git a/opal/event/event.c b/opal/event/event.c
index aea2be00a8..1a254018eb 100644
--- a/opal/event/event.c
+++ b/opal/event/event.c
@@ -227,7 +227,7 @@ opal_event_init(void)
 
 #if OPAL_HAVE_WORKING_EVENTOPS
 
-	if ((current_base = (event_base*)calloc(1, sizeof(struct event_base))) == NULL)
+	if ((current_base = (struct event_base*)calloc(1, sizeof(struct event_base))) == NULL)
 		event_err(1, "%s: calloc");
 
 	event_sigcb = NULL;
diff --git a/opal/tools/wrappers/opal_wrapper.c b/opal/tools/wrappers/opal_wrapper.c
index 82702e3c43..9d4dfd4d67 100644
--- a/opal/tools/wrappers/opal_wrapper.c
+++ b/opal/tools/wrappers/opal_wrapper.c
@@ -324,11 +324,11 @@ main(int argc, char *argv[])
 #if defined(EXEEXT)
     if( 0 != strlen(EXEEXT) ) {
         char extension[] = EXEEXT;
-        char* temp = strstr( base_argv0, EXEEXT );
+        char* temp = strstr( base_argv0, extension );
         char* old_match = temp;
         while( NULL != temp ) {
             old_match = temp;
-            temp = strstr( temp + 1, EXEEXT );
+            temp = strstr( temp + 1, extension );
         }
         *old_match = '\0';
     }
diff --git a/opal/util/cmd_line.c b/opal/util/cmd_line.c
index f3b20a9a96..7cb20273a8 100644
--- a/opal/util/cmd_line.c
+++ b/opal/util/cmd_line.c
@@ -555,7 +555,7 @@ char *opal_cmd_line_get_usage_msg(opal_cmd_line_t *cmd)
             }
             strcat(line, " ");
             for (i = 0; (int)i < option->clo_num_params; ++i) {
-                snprintf(temp, len, "<arg%d> ", i);
+                snprintf(temp, len, "<arg%d> ", (int)i);
                 strcat(line, temp);
             }
             if (option->clo_num_params > 0) {
diff --git a/opal/util/keyval/keyval_lex.l b/opal/util/keyval/keyval_lex.l
index 105e900a3b..0bedabe59a 100644
--- a/opal/util/keyval/keyval_lex.l
+++ b/opal/util/keyval/keyval_lex.l
@@ -30,7 +30,13 @@
  * local functions
  */
 static int finish_parsing(void);
-extern "C" int opal_util_keyval_yywrap(void);
+#if defined(c_plusplus) || defined(__cplusplus)
+extern "C" {
+#endif
+int opal_util_keyval_yywrap(void);
+#if defined(c_plusplus) || defined(__cplusplus)
+}
+#endif
 
 /*
  * global variables
@@ -94,7 +100,7 @@ static int finish_parsing(void)
     return YY_NULL;
 }
 
-static int opal_util_keyval_yywrap(void)
+int opal_util_keyval_yywrap(void)
 {
     opal_util_keyval_parse_done = true;
     return 1;
diff --git a/opal/util/printf.c b/opal/util/printf.c
index 533d0ea292..583b44a47a 100644
--- a/opal/util/printf.c
+++ b/opal/util/printf.c
@@ -91,7 +91,7 @@ static int guess_strlen(const char *fmt, va_list ap)
                 break;
 
             case 'f':
-                farg = va_arg(ap, float);
+                farg = va_arg(ap, int);
                 /* Alloc for minus sign */
                 if (farg < 0) {
                     ++len;