Submitted by: @pavel-zotov

Run following script:

recreate table test (
id int,
val int
);
commit;
insert into test(id, val) values (1, 10);
commit;
set term ^;
execute block as
declare curVal integer;
declare curID integer;
begin
for select id, val
from test
where id = 1
into curid, curval
as cursor cur1
do begin
update test
set val=123
where current of cur1;
rdb$set_context('USER_SESSION','EXE_BLOCK_UPDATE_1_ROW_COUNT', row_count );

    update test
    set val=456
    where current of cur1;
    rdb$set\_context\('USER\_SESSION','EXE\_BLOCK\_UPDATE\_2\_ROW\_COUNT', row\_count \);
    
    update test
    set val=789
    where current of cur1;
    rdb$set\_context\('USER\_SESSION','EXE\_BLOCK\_UPDATE\_3\_ROW\_COUNT', row\_count \);
end

end
^
set term ;^

set list on;
select mon$variable_name as ctx_var, mon$variable_value as ctx_value from mon$context_variables;

quit;

Its output will be:

CTX_VAR EXE_BLOCK_UPDATE_1_ROW_COUNT
CTX_VALUE 1

CTX_VAR EXE_BLOCK_UPDATE_2_ROW_COUNT
CTX_VALUE 2

CTX_VAR EXE_BLOCK_UPDATE_3_ROW_COUNT
CTX_VALUE 3

Value of ROW_COUNT was incremented by 1 all subsequent UPDATE statements that was executed within cursor ("where current of cursor cur1").