For update clause

Hi,

I am one of the french translators of the documentation. I am translating the
reference page of SELECT, but I fail to understand this sentence about the FOR
UPDATE clause (  http://www.postgresql.org/docs/9.0/static/sql-
select.html#SQL-FOR-UPDATE-SHARE   )

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In addition, rows that satisfied the query conditions as of the query snapshot
will be locked, although they will not be returned if they have since been
updated to not satisfy the query conditions.
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Could anyone please explain it to me, so that I can translate it properly? A
word for word translation has really no meaning.


Florence