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/*!
    \contentspage list-of-language-items.html
    \previouspage module-item.html
    \page probe-item.html
    \nextpage product-item.html
    \ingroup list-of-language-items
    \ingroup list-of-items

    \title Probe Item
    \brief Locates files outside the project.

    \c Probe items can appear inside \l{Product Item}{products} and \l{Project Item}{projects}.
    They are run prior to building, for instance to locate dependent headers, libraries, and other
    files outside the project directory whose locations are not known ahead of time.
    Probes can be parameterized via their properties and typically store results in
    properties as well. These results are then retrieved via the Probe's id, which is mandatory:
    \code
    Product {
        Probe {
            id: valueCalculator
            property string parameter: "whatever"
            property int value
            configure: {
                value = Utils.calculateValue(parameter); // Expensive operation
                found = true;
            }
        }
        property int theValue: valueCalculator.value
    }
    \endcode

    \note Because Probes often invoke external processes, which is relatively expensive compared
          to evaluating normal properties, their results are cached. To force re-evaluation
          of a Probe, you can supply the \c{--force-probe-execution} command-line option.

    \section1 Probe Properties

    \table
    \header
        \li Property
        \li Type
        \li Default
        \li Description
    \row
        \li condition
        \li bool
        \li true
        \li Determines whether the probe will actually be run.
    \row
        \li found
        \li bool
        \li undefined
        \li Indicates whether the probe was run successfully. Set by \c configure.
    \row
        \li configure
        \li script
        \li undefined
        \li Script that is executed when the probe is run.
    \endtable

*/