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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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