[PATCH 7/7] doc: describe how values match sets

[Christoph Anton Mitterer <mail@christoph.anton.mitterer.name>]

Signed-off-by: Christoph Anton Mitterer <mail@christoph.anton.mitterer.name>
---
 doc/nft.txt | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/doc/nft.txt b/doc/nft.txt
index 899c38d6..7e75381d 100644
--- a/doc/nft.txt
+++ b/doc/nft.txt
@@ -741,6 +741,16 @@ Example: When the set contains range *1.2.3.1-1.2.3.4*, then adding element *1.2
 effect.  Adding *1.2.3.5* changes the existing range to cover *1.2.3.1-1.2.3.5*.
 Without this flag, *1.2.3.2* can not be added and *1.2.3.5* is inserted as a new entry.
 
+Equality of a value with a set is given if the value matches exactly one value
+in the set.
+It shall be noted that for bitmask values this means, that
+*'expression' 'bit'[,'bit']...* (which yields true if *any* of the bits are set)
+is not the same as *'expression' {'bit'[,'bit']...}* (which yields true if
+exactly one of the bits are set).
+It may however be (effectively) the same, in cases like
+`ct state established,related` and `ct state {established,related}`, where these
+states are mutually exclusive.
+
 MAPS
 -----
 [verse]
-- 
2.51.0