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Motif and CDE 2.1 Style Guide Reference
Warning Signal
Reference
Description
A warning signal is a transient cue that alerts the user about a minor,
nonfatal error or problem with interaction. A warning signal may be an audible
signal (such as a beep) or a visible signal (such as a flashing screen) or
both. A warning signal may also be other transient, sensory signals that the
operating environment supports. The warning signal should use as many modes as
needed to supplement other on-screen cues. For example, if the user is in a
low-light environment, an audible signal can be a useful supplement to other
visible on-screen messages and graphical cues.
When to Use
- Required
- Provide a warning signal when the user types a character that is not
supported as input for a text-entry field that has focus. For example, if a
text-entry field supports only numeric characters, provide a warning signal
when the user types a letter.
- Required
- Provide a warning signal when the user types a character that cannot be
used as a mnemonic at the active cursor position or the control on which the
cursor is positioned does not accept text input. For example, if mnemonics are
supported but no choice has L assigned as the mnemonic, provide a warning
signal when the user presses the L key.
- Required
- Use a warning signal to supplement a message. Note that in degraded
environments, a message may occur in sensory modalities other than the
standard visual on-screen mode. See Chapter
12 for more information.
- Recommended
- Provide a warning signal when a user attempts to activate a choice or
interact with a control that is displayed with unavailable emphasis.
- Recommended
- Provide a warning signal to supplement a persistent cue that might
otherwise be ignored by the user, or if the cue is intended to alert the user,
or if the situation is urgent.
Guidelines
- Required
- If the user has turned off a warning signal option for the operating
environment and a situation arises in which the system would normally generate
that warning signal, do not generate a warning signal. For example, if the
user has turned off audible signals for the operating environment, do not
generate an audible signal when an action message is displayed.
- Recommended
- Allow the user to take advantage of various capabilities of hardware and
software. For example, if the operating environment supports the generation of
a variety of sounds, allow the user to specify different sounds for a warning
message, an action message, and for an attempt to activate a choice currently
displayed with unavailable emphasis.
- Recommended
- Even if the operating environment allows an unlimited range of warning
signals in any sensory modality, assign meaning to only a limited number of
signals. Generally, your application should support no more than seven
different audible signals and about five different visible signals.
- Recommended
- If a warning signal is the only indication of a condition and the
environment is degraded such that a warning signal cannot be used effectively,
use a warning message instead.
Essential Related Topics
For more information, see Chapter
4 and the Action Message, Message, and Persistent Cue reference pages.
Supplemental Related Topics
For more information, see the Information and Message Areas (Area) and
Mnemonic reference pages.
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