is the list of rules that gives named message groups used in functions like On and Quiet.


  • The value of $MessageGroups has the form {"name":>{symbol::tag,},}.
  • Named groups can also appear on the right-hand side of the definitions.
  • $MessageGroups can be reset. Any string can be used as the name of a message group.
  • Named message groups can be used in On, Off, Check, Quiet.
  • Predefined named message groups include:
  • "Compiler"warnings associated with compiled code
    "Graphics"warnings associated with graphics generation
    "Obsolete"warnings for obsolete functions and packages
    "Packing"notifications associated with packed arrays
    "Spelling"spell-checking messages for symbol names
    "Symbolics"warnings associated with symbolic computation


open allclose all

Basic Examples  (1)

Get the list of the existing message groups:

Scope  (1)

Get the list of messages associated with packed arrays:

Define a new group comprised of the existing groups:

Applications  (2)

Check for unpacking of arrays:

This produces rational numbers and has to unpack:

Using inexact numbers leaves the array packed:

Quiet the compiler warnings that allow the evaluation to proceed:

Introduced in 2008