diff --git a/src/platform.h b/src/platform.h
index 952668c6..ffff4c97 100644
--- a/src/platform.h
+++ b/src/platform.h
@@ -137,13 +137,15 @@ const char *_getdns_strerror(int errnum);
 void _getdns_perror(const char *str);
 
 #define _getdns_errnostr() (_getdns_strerror(_getdns_socketerror()))
-#define _getdns_error_wants_retry(X) (  (X) == _getdns_EINTR \
-                                     || (X) == _getdns_EAGAIN \
-                                     || (X) == _getdns_EWOULDBLOCK \
-                                     || (X) == _getdns_EINPROGRESS \
-                                     || (X) == _getdns_ENOBUFS )
+#define _getdns_error_wants_retry(X) (  (X) != 0 \
+                                     && (  (X) == _getdns_EINTR \
+                                        || (X) == _getdns_EAGAIN \
+                                        || (X) == _getdns_EWOULDBLOCK \
+                                        || (X) == _getdns_EINPROGRESS \
+                                        || (X) == _getdns_ENOBUFS ))
 #define _getdns_socket_wants_retry() (_getdns_error_wants_retry(_getdns_socketerror()))
-#define _getdns_resource_depletion() (  _getdns_socketerror() == _getdns_ENFILE \
-                                     || _getdns_socketerror() == _getdns_EMFILE )
+#define _getdns_resource_depletion() (  _getdns_socketerror() != 0 \
+                                     && (  _getdns_socketerror() == _getdns_ENFILE \
+                                        || _getdns_socketerror() == _getdns_EMFILE ))
 
 #endif