[REBOL] Re: callbacks

From: gregg:pointillistic at: 1-Nov-2007 10:11

Hi Max,

I did something similar a few years ago. Not callback related, but
filling a struct with data allocated by an API (IIRC).

    get-dereferenced-data: func [
        {Given a pointer to memory, copy the target data into a REBOL struct.}
        pointer [struct!]   "LPINT structure whose /value is the data pointer"
        struct-def [block!] "The struct you want returned with data"
        /local struct data orig-pointer result
    ] [
        struct: make struct! compose/deep/only [ ; make wrapper struct
            sub [struct! (struct-def)]
        ] none
        orig-pointer: third struct              ; store original inner pointer
        change third struct third pointer       ; change inner pointer to ref'd data
        data: copy third struct/sub             ; copy data from the inner struct
        change third struct orig-pointer        ; restore inner pointer
        result: make struct! struct-def none    ; make result struct
        change third result data                ; change data in result struct
        struct: data: orig-pointer: none
        result
    ]

-- Gregg

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