Variable: history-length
history-length is a customizable variable defined in minibuf.c.
Value
100
Documentation
Maximum length of history lists before truncation takes place.
A number means truncate to that length; truncation deletes old elements, and is done just after inserting a new element. A value of t means no truncation.
This variable only affects history lists that don't specify their own
maximum lengths. Setting the history-length property of a history
variable overrides this default.
This variable was added, or its default value changed, in Emacs 24.5.
Probably introduced at or before Emacs version 20.1.
Source Code
// Defined in /usr/src/emacs/src/minibuf.c
DEFVAR_LISP ("history-length", Vhistory_length,
doc: /* Maximum length of history lists before truncation takes place.
A number means truncate to that length; truncation deletes old
elements, and is done just after inserting a new element.
A value of t means no truncation.
This variable only affects history lists that don't specify their own
maximum lengths. Setting the `history-length' property of a history
variable overrides this default. */);