--- src/libc/compat/stdio/fseeko64.c
+++ src/libc/compat/stdio/fseeko64.c
@@ -19,6 +19,8 @@ fseeko64(FILE *_stream, off64_t _offset,
   o = llseek(fileno(_stream), _offset, _mode);
   if (o == -1)
     return -1;
+  if (_stream)
+    _stream->_cnt = 0;
   return 0;
 }