It is possible to have any
number of Calc mode buffers at once. Usually this is done by
executing M-x another-calc, which is similar to
C-x * c except that if a ‘*Calculator*’ buffer already exists, a
new, independent one with a name of the form
‘*Calculator*<n>’ is created. You can also use the
command calc-mode to put any buffer into Calculator
mode, but this would ordinarily never be done.
The q (calc-quit) command does not
destroy a Calculator buffer; it only closes its window. Use
M-x kill-buffer to destroy a Calculator buffer.
Each Calculator buffer keeps its own stack, undo list, and
mode settings such as precision, angular mode, and display
formats. In Emacs terms, variables such as
calc-stack are buffer-local variables. The global
default values of these variables are used only when a new
Calculator buffer is created. The calc-quit command
saves the stack and mode settings of the buffer being quit as the
new defaults.
There is only one trail buffer, ‘*Calc Trail*’, used by all Calculator buffers.