History Variables
=================

   This section describes the externally visible variables exported by
the GNU History Library.

 - Variable: int history_base
     The logical offset of the first entry in the history list.

 - Variable: int history_length
     The number of entries currently stored in the history list.

 - Variable: int max_input_history
     The maximum number of history entries.  This must be changed using
     `stifle_history ()'.

 - Variable: char history_expansion_char
     The character that starts a history event.  The default is `!'.

 - Variable: char history_subst_char
     The character that invokes word substitution if found at the start
     of a line.  The default is `^'.

 - Variable: char history_comment_char
     During tokenization, if this character is seen as the first
     character of a word, then it and all subsequent characters up to a
     newline are ignored, suppressing history expansion for the
     remainder of the line.  This is disabled by default.

 - Variable: char * history_no_expand_chars
     The list of characters which inhibit history expansion if found
     immediately following HISTORY_EXPANSION_CHAR.  The default is
     whitespace and `='.

 - Variable: char * history_search_delimiter_chars
     The list of additional characters which can delimit a history
     search string, in addition to whitespace, `:' and `?' in the case
     of a substring search.  The default is empty.

 - Variable: int history_quotes_inhibit_expansion
     If non-zero, single-quoted words are not scanned for the history
     expansion character.  The default value is 0.