inotify_add_watch flag to prevent modifying existing watch descriptors, when used on an already watched inode it fails with EEXIST. added in linux commit 4d97f7d53da7dc830dbf416a3d2a6778d267ae68
@@ -40,6 +40,7 @@ struct inotify_event {
#define IN_ONLYDIR 0x01000000
#define IN_DONT_FOLLOW 0x02000000
#define IN_EXCL_UNLINK 0x04000000
+#define IN_MASK_CREATE 0x10000000
#define IN_MASK_ADD 0x20000000
#define IN_ISDIR 0x40000000