Return err when any message is issued:

Check only for specific messages:

Check for a message from a specific function:

The ArcTan::indet is not caught by Check:

Use the head General to catch the message from any function:

Catch multiple messages:

Check for a message from a named group:

Use Check and Quiet to provide values for arguments where a function is not applicable:

This function simply returns its argument if its argument is a string of length less than four:

Without the Check and Quiet, the middle input would have returned unevaluated with a message:

Check does not prevent messages from being issued:

Check does not detect messages suppressed with a inner Quiet:

However, the operation of Check is not affected by being inside Quiet:

Check does not report messages that have been turned off:

Restore the message:

A nested Check does not silence a message for an enclosing Check:

Use an intermediate Quiet to prevent the enclosing Check from reacting to the message: