diff --git a/configure.ac b/configure.ac
index f3b35c98..8ae4d4db 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1101,17 +1101,16 @@ AH_BOTTOM([
 #endif
 
 #ifdef GETDNS_ON_WINDOWS
-/* On windows it is allowed to increase the FD_SETSIZE
- * (and nescessary to make our custom eventloop work)
- * See: https://support.microsoft.com/en-us/kb/111855
- */
-#ifndef FD_SETSIZE
-#define FD_SETSIZE 1024
-#endif
-
-#define PRIsz "%Iu"
+ /* On windows it is allowed to increase the FD_SETSIZE
+  * (and nescessary to make our custom eventloop work)
+  * See: https://support.microsoft.com/en-us/kb/111855
+  */
+# ifndef FD_SETSIZE
+# define FD_SETSIZE 1024
+# endif
+# define PRIsz "%Iu"
 #else
-#define PRIsz "%zu"
+# define PRIsz "%zu"
 #endif
 
 #include <stdint.h>
@@ -1148,8 +1147,6 @@ AH_BOTTOM([
 #define FD_SET_T 
 #endif
 
-
-
 #ifdef __cplusplus
 extern "C" {
 #endif
@@ -1204,6 +1201,12 @@ int inet_pton(int af, const char* src, void* dst);
 const char *inet_ntop(int af, const void *src, char *dst, size_t size);
 #endif
 
+#ifdef USE_WINSOCK
+static inline int _gldns_custom_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; }
+# define vsnprintf _gldns_custom_vsnprintf
+#endif
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/src/gldns/gbuffer.c b/src/gldns/gbuffer.c
index cecfe480..77398905 100644
--- a/src/gldns/gbuffer.c
+++ b/src/gldns/gbuffer.c
@@ -133,8 +133,8 @@ gldns_buffer_printf(gldns_buffer *buffer, const char *format, ...)
 
 		remaining = gldns_buffer_remaining(buffer);
 		va_start(args, format);
-		written = _gldns_vsnprintf((char*)gldns_buffer_current(buffer),
-		    remaining, format, args);
+		written = vsnprintf((char *) gldns_buffer_current(buffer), remaining,
+				    format, args);
 		va_end(args);
 		if (written == -1) {
 			buffer->_status_err = 1;
@@ -145,8 +145,7 @@ gldns_buffer_printf(gldns_buffer *buffer, const char *format, ...)
 				return -1;
 			}
 			va_start(args, format);
-			written = _gldns_vsnprintf(
-			    (char *) gldns_buffer_current(buffer),
+			written = 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 67539424..15dca675 100644
--- a/src/gldns/gbuffer.h
+++ b/src/gldns/gbuffer.h
@@ -27,21 +27,6 @@ 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).
@@ -175,7 +160,7 @@ gldns_buffer_invariant(gldns_buffer *buffer)
 	assert(buffer != NULL);
 	assert(buffer->_position <= buffer->_limit || buffer->_vfixed);
 	assert(buffer->_limit <= buffer->_capacity);
-	assert(buffer->_data != NULL || (buffer->_capacity == 0 && buffer->_vfixed));
+	assert(buffer->_data != NULL || (buffer->_vfixed && buffer->_capacity == 0));
 }
 #endif
 
@@ -210,7 +195,7 @@ void gldns_buffer_init_frm_data(gldns_buffer *buffer, void *data, size_t size);
 /**
  * Setup a buffer with the data pointed to. No data copied, no memory allocs.
  * The buffer is fixed.  Writes beyond size (the capacity) will update the 
- * position (and not write data.  This allows to determine how big the buffer
+ * position (and not write data).  This allows to determine how big the buffer
  * should have been to contain all the written data.
  * \param[in] buffer pointer to the buffer to put the data in
  * \param[in] data the data to encapsulate in the buffer
diff --git a/src/gldns/wire2str.c b/src/gldns/wire2str.c
index 50d00967..2d427d86 100644
--- a/src/gldns/wire2str.c
+++ b/src/gldns/wire2str.c
@@ -279,7 +279,7 @@ 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 = _gldns_vsnprintf(*str, *slen, format, args);
+	int w = vsnprintf(*str, *slen, format, args);
 	if(w < 0) {
 		/* error in printout */
 		return 0;