1 files changed, 1 insertions, 1 deletions
diff --git a/pb_encode.c b/pb_encode.c
index 221c0ea..64b62b4 100644
--- a/pb_encode.c
+++ b/pb_encode.c
@@ -100,7 +100,7 @@ pb_ostream_t pb_ostream_from_buffer(pb_byte_t *buf, size_t bufsize)
 
 bool checkreturn pb_write(pb_ostream_t *stream, const pb_byte_t *buf, size_t count)
 {
-    if (stream->callback != NULL)
+    if (count > 0 && stream->callback != NULL)
     {
         if (stream->bytes_written + count > stream->max_size)
             PB_RETURN_ERROR(stream, "stream full");