GNU Emacs Calc 2.02 Manual

7.4.7: Automatic Recomputation

The evaluates-to operator, `=>', has the special property that any `=>' formulas on the stack are recomputed whenever variable values or mode settings that might affect them are changed. See Evaluates-To Operator.

The m C (calc-auto-recompute) command turns this automatic recomputation on and off. If you turn it off, Calc will not update `=>' operators on the stack (nor those in the attached Embedded Mode buffer, if there is one). They will not be updated unless you explicitly do so by pressing = or until you press m C to turn recomputation back on. (While automatic recomputation is off, you can think of m C m C as a command to update all `=>' operators while leaving recomputation off.)

To update `=>' operators in an Embedded buffer while automatic recomputation is off, use M-# u. See Embedded Mode.