The eCos Component Writer's Guide
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# description

## Name

Property description -- Provide a textual description for an option.

## Synopsis

    cdl_option <name> {
        description <text>
        …
    }

## Description

Users can only be expected to manipulate configuration options sensibly if they are given sufficient information about these options. There are three properties which serve to explain an option in plain text: the display property gives a textual alias for an option, which is usually more comprehensible than something like `CYGPKG_LIBC_TIME_ZONES`; the description property gives a longer description, typically a paragraph or so; the doc property specifies the location of additional on-line documentation related to a configuration option. In the context of a graphical tool the display string will be the primary way for users to identify configuration options; the description paragraph will be visible whenever the option is selected; the on-line documentation will only be accessed when the user explicitly requests it.

At present there is no way of providing any sort of formatting mark-up in a description. It is possible that future versions of the configuration tools will provide some control over the way the description text gets rendered.

## Example

    cdl_option CYGDBG_INFRA_DEBUG_TRACE_MESSAGE {
        display       "Use trace text"
        default_value 1
        description   "
            All trace calls within eCos contain a text message
            which should give some information about the circumstances.
            These text messages will end up being embedded in the
            application image and hence there is a significant penalty
            in terms of image size.
            It is possible to suppress the use of these messages by
            disabling this option.
            This results in smaller code size, but there is less
            human-readable information available in the trace output,
            possibly only filenames and line numbers."
    }

## See Also

Properties display and doc.

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