diff --git a/src/gldns/gbuffer.c b/src/gldns/gbuffer.c
index a73281c5..ac70415d 100644
--- a/src/gldns/gbuffer.c
+++ b/src/gldns/gbuffer.c
@@ -120,8 +120,8 @@ gldns_buffer_printf(gldns_buffer *buffer, const char *format, ...)
 
 		remaining = gldns_buffer_remaining(buffer);
 		va_start(args, format);
-		written = vsnprintf((char *) gldns_buffer_current(buffer), remaining,
-				    format, args);
+		written = _gldns_vsnprintf((char*)gldns_buffer_current(buffer),
+		    remaining, format, args);
 		va_end(args);
 		if (written == -1) {
 			buffer->_status_err = 1;
@@ -132,7 +132,8 @@ gldns_buffer_printf(gldns_buffer *buffer, const char *format, ...)
 				return -1;
 			}
 			va_start(args, format);
-			written = vsnprintf((char *) gldns_buffer_current(buffer),
+			written = _gldns_vsnprintf(
+			    (char *) gldns_buffer_current(buffer),
 			    gldns_buffer_remaining(buffer), format, args);
 			va_end(args);
 			if (written == -1) {
diff --git a/src/gldns/gbuffer.h b/src/gldns/gbuffer.h
index 745bb8eb..3d3190ed 100644
--- a/src/gldns/gbuffer.h
+++ b/src/gldns/gbuffer.h
@@ -27,6 +27,21 @@ extern "C" {
 #  endif
 #endif
 
+#ifndef USE_WINSOCK
+#define _gldns_vsnprintf vsnprintf
+#else
+/* Unlike Linux and BSD, vsnprintf on Windows returns -1 on overflow.
+ * Here it is redefined to always return the amount printed
+ * if enough space had been available.
+ */
+INLINE int
+_gldns_vsnprintf(char *str, size_t size, const char *format, va_list ap)
+{
+	int r = vsnprintf(str, size, format, ap);
+	return r == -1 ? _vscprintf(format, ap) : r;
+}
+#endif
+
 /*
  * Copy data allowing for unaligned accesses in network byte order
  * (big endian).
diff --git a/src/gldns/wire2str.c b/src/gldns/wire2str.c
index f15631b0..b9a979eb 100644
--- a/src/gldns/wire2str.c
+++ b/src/gldns/wire2str.c
@@ -278,7 +278,7 @@ int gldns_wire2str_dname_buf(uint8_t* d, size_t dlen, char* s, size_t slen)
 
 int gldns_str_vprint(char** str, size_t* slen, const char* format, va_list args)
 {
-	int w = vsnprintf(*str, *slen, format, args);
+	int w = _gldns_vsnprintf(*str, *slen, format, args);
 	if(w < 0) {
 		/* error in printout */
 		return 0;
diff --git a/src/test/getdns_query.c b/src/test/getdns_query.c
index 837ed61d..73e2c11c 100644
--- a/src/test/getdns_query.c
+++ b/src/test/getdns_query.c
@@ -68,12 +68,13 @@ my_eventloop_schedule(getdns_eventloop *loop,
 	my_eventloop *my_loop  = (my_eventloop *)loop;
 	size_t        i;
 
+	DEBUG_SCHED( "%s(loop: %p, fd: %d, timeout: %"PRIu64", event: %p, FD_SETSIZE: %d)\n"
+	        , __FUNCTION__, loop, fd, timeout, event, FD_SETSIZE);
+
 	assert(loop);
 	assert(event);
 	assert(fd < FD_SETSIZE);
 
-	DEBUG_SCHED( "%s(loop: %p, fd: %d, timeout: %"PRIu64", event: %p)\n"
-	        , __FUNCTION__, loop, fd, timeout, event);
 	if (fd >= 0 && (event->read_cb || event->write_cb)) {
 		assert(my_loop->fd_events[fd] == NULL);