Read lifo
Purpose: Reads key/value pair from a LIFO list.

read-lifo <list> \
    key <key> \
    value <value> \
    [ status <status> ]

read-lifo retrieves an element from the LIFO <list> into <key> string  (in "key" clause) and <value> string (in "value" clause).

Once an element has been retrieved, the next use of read-lifo will obtain the following one, in the reverse order they were put in. read-lifo starts with the last element put in, and moves backwards from there, unless rewind-lifo is called, which positions back to the last one. Note that write-lifo will cause the next read-lifo to start with the element just written, i.e. it implicitly calls rewind-lifo.

If the element is successfully retrieved, <status> number (in "status" clause) is GG_OKAY, otherwise it is GG_ERR_EXIST, which means there are no more elements to retrieve.
Examples
In this example, a LIFO list is created, and two key/value pairs added. They are then retrieved in a loop and printed out (twice with rewind), and then the list is purged:
%% /lifo public
    new-lifo mylist

    // Add data to the list
    write-lifo mylist key "key1" value "value1"
    write-lifo mylist key "some2" value "other2"

    start-loop
       // Get data from the list
       read-lifo mylist key k value v status st

       // Check if no more data
       if-true st not-equal GG_OKAY
           break-loop
       end-if

       @Obtained key <<print-out k>> with value <<print-out v>>
    end-loop

    // Go through the list again, use rewind-lifo for that
    rewind-lifo mylist

    start-loop
       read-lifo mylist key k value v status st
       if-true st not-equal GG_OKAY
           break-loop
       end-if
       @Again obtained key <<print-out k>> with value <<print-out v>>
    end-loop

    // Delete all in LIFO
    purge-lifo mylist
    // Verify nothing is left
    rewind-lifo mylist
    read-lifo mylist key k value v status st
    if-true st not-equal GG_OKAY
       @LIFO is empty
    end-if
%%

See also
LIFO
delete-lifo  
get-lifo  
new-lifo  
purge-lifo  
read-lifo  
rewind-lifo  
write-lifo  
See all
documentation

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