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diff --git a/readline/doc/hstech.texinfo b/readline/doc/hstech.texinfo index 12fff2c9a75..949444668fc 100644 --- a/readline/doc/hstech.texinfo +++ b/readline/doc/hstech.texinfo @@ -1,7 +1,7 @@ @ignore This file documents the user interface to the GNU History library. -Copyright (C) 1988, 1991, 1994, 1996 Free Software Foundation, Inc. +Copyright (C) 1988-2002 Free Software Foundation, Inc. Authored by Brian Fox and Chet Ramey. Permission is granted to make and distribute verbatim copies of this manual @@ -27,9 +27,9 @@ into another language, under the above conditions for modified versions. @chapter Programming with GNU History This chapter describes how to interface programs that you write -with the GNU History Library. +with the @sc{gnu} History Library. It should be considered a technical guide. -For information on the interactive use of GNU History, @pxref{Using +For information on the interactive use of @sc{gnu} History, @pxref{Using History Interactively}. @menu @@ -43,10 +43,10 @@ History Interactively}. @node Introduction to History @section Introduction to History -Many programs read input from the user a line at a time. The GNU History -library is able to keep track of those lines, associate arbitrary data with -each line, and utilize information from previous lines in composing new -ones. +Many programs read input from the user a line at a time. The @sc{gnu} +History library is able to keep track of those lines, associate arbitrary +data with each line, and utilize information from previous lines in +composing new ones. The programmer using the History library has available functions for remembering lines on a history list, associating arbitrary data @@ -80,9 +80,11 @@ The history list is an array of history entries. A history entry is declared as follows: @example +typedef void *histdata_t; + typedef struct _hist_entry @{ char *line; - char *data; + histdata_t data; @} HIST_ENTRY; @end example @@ -95,12 +97,14 @@ HIST_ENTRY **the_history_list; The state of the History library is encapsulated into a single structure: @example -/* A structure used to pass the current state of the history stuff around. */ +/* + * A structure used to pass around the current state of the history. + */ typedef struct _hist_state @{ - HIST_ENTRY **entries; /* Pointer to the entries themselves. */ - int offset; /* The location pointer within this array. */ - int length; /* Number of elements within this array. */ - int size; /* Number of slots allocated to this array. */ + HIST_ENTRY **entries; /* Pointer to the entries themselves. */ + int offset; /* The location pointer within this array. */ + int length; /* Number of elements within this array. */ + int size; /* Number of slots allocated to this array. */ int flags; @} HISTORY_STATE; @end example @@ -112,7 +116,7 @@ stifled. @section History Functions This section describes the calling sequence for the various functions -present in GNU History. +exported by the @sc{gnu} History library. @menu * Initializing History and State Management:: Functions to call when you @@ -139,12 +143,12 @@ This section describes functions used to initialize and manage the state of the History library when you want to use the history functions in your program. -@deftypefun void using_history () +@deftypefun void using_history (void) Begin a session in which the history functions might be used. This initializes the interactive variables. @end deftypefun -@deftypefun {HISTORY_STATE *} history_get_history_state () +@deftypefun {HISTORY_STATE *} history_get_history_state (void) Return a structure describing the current state of the input history. @end deftypefun @@ -158,7 +162,7 @@ Set the state of the history list according to @var{state}. These functions manage individual entries on the history list, or set parameters managing the list itself. -@deftypefun void add_history (char *string) +@deftypefun void add_history (const char *string) Place @var{string} at the end of the history list. The associated data field (if any) is set to @code{NULL}. @end deftypefun @@ -169,13 +173,13 @@ removed element is returned so you can free the line, data, and containing structure. @end deftypefun -@deftypefun {HIST_ENTRY *} replace_history_entry (int which, char *line, char *data) +@deftypefun {HIST_ENTRY *} replace_history_entry (int which, const char *line, histdata_t data) Make the history entry at offset @var{which} have @var{line} and @var{data}. This returns the old entry so you can dispose of the data. In the case of an invalid @var{which}, a @code{NULL} pointer is returned. @end deftypefun -@deftypefun void clear_history () +@deftypefun void clear_history (void) Clear the history list by deleting all the entries. @end deftypefun @@ -183,13 +187,14 @@ Clear the history list by deleting all the entries. Stifle the history list, remembering only the last @var{max} entries. @end deftypefun -@deftypefun int unstifle_history () -Stop stifling the history. This returns the previous amount the -history was stifled. The value is positive if the history was +@deftypefun int unstifle_history (void) +Stop stifling the history. This returns the previously-set +maximum number of history entries (as set by @code{stifle_history()}). +The value is positive if the history was stifled, negative if it wasn't. @end deftypefun -@deftypefun int history_is_stifled () +@deftypefun int history_is_stifled (void) Returns non-zero if the history is stifled, zero if it is not. @end deftypefun @@ -199,29 +204,30 @@ Returns non-zero if the history is stifled, zero if it is not. These functions return information about the entire history list or individual list entries. -@deftypefun {HIST_ENTRY **} history_list () -Return a @code{NULL} terminated array of @code{HIST_ENTRY} which is the +@deftypefun {HIST_ENTRY **} history_list (void) +Return a @code{NULL} terminated array of @code{HIST_ENTRY *} which is the current input history. Element 0 of this list is the beginning of time. If there is no history, return @code{NULL}. @end deftypefun -@deftypefun int where_history () +@deftypefun int where_history (void) Returns the offset of the current history element. @end deftypefun -@deftypefun {HIST_ENTRY *} current_history () +@deftypefun {HIST_ENTRY *} current_history (void) Return the history entry at the current position, as determined by -@code{where_history ()}. If there is no entry there, return a @code{NULL} +@code{where_history()}. If there is no entry there, return a @code{NULL} pointer. @end deftypefun @deftypefun {HIST_ENTRY *} history_get (int offset) Return the history entry at position @var{offset}, starting from -@code{history_base}. If there is no entry there, or if @var{offset} +@code{history_base} (@pxref{History Variables}). +If there is no entry there, or if @var{offset} is greater than the history length, return a @code{NULL} pointer. @end deftypefun -@deftypefun int history_total_bytes () +@deftypefun int history_total_bytes (void) Return the number of bytes that the primary history entries are using. This function returns the sum of the lengths of all the lines in the history. @@ -234,17 +240,19 @@ These functions allow the current index into the history list to be set or changed. @deftypefun int history_set_pos (int pos) -Set the position in the history list to @var{pos}, an absolute index +Set the current history offset to @var{pos}, an absolute index into the list. +Returns 1 on success, 0 if @var{pos} is less than zero or greater +than the number of history entries. @end deftypefun -@deftypefun {HIST_ENTRY *} previous_history () +@deftypefun {HIST_ENTRY *} previous_history (void) Back up the current history offset to the previous history entry, and return a pointer to that entry. If there is no previous entry, return a @code{NULL} pointer. @end deftypefun -@deftypefun {HIST_ENTRY *} next_history () +@deftypefun {HIST_ENTRY *} next_history (void) Move the current history offset forward to the next history entry, and return the a pointer to that entry. If there is no next entry, return a @code{NULL} pointer. @@ -260,26 +268,28 @@ from the current history position. The search may be @dfn{anchored}, meaning that the string must match at the beginning of the history entry. @cindex anchored search -@deftypefun int history_search (char *string, int direction) -Search the history for @var{string}, starting at the current history -offset. If @var{direction} < 0, then the search is through previous entries, -else through subsequent. If @var{string} is found, then +@deftypefun int history_search (const char *string, int direction) +Search the history for @var{string}, starting at the current history offset. +If @var{direction} is less than 0, then the search is through +previous entries, otherwise through subsequent entries. +If @var{string} is found, then the current history index is set to that history entry, and the value returned is the offset in the line of the entry where @var{string} was found. Otherwise, nothing is changed, and a -1 is returned. @end deftypefun -@deftypefun int history_search_prefix (char *string, int direction) +@deftypefun int history_search_prefix (const char *string, int direction) Search the history for @var{string}, starting at the current history offset. The search is anchored: matching lines must begin with -@var{string}. If @var{direction} < 0, then the search is through previous -entries, else through subsequent. If @var{string} is found, then the +@var{string}. If @var{direction} is less than 0, then the search is +through previous entries, otherwise through subsequent entries. +If @var{string} is found, then the current history index is set to that entry, and the return value is 0. Otherwise, nothing is changed, and a -1 is returned. @end deftypefun -@deftypefun int history_search_pos (char *string, int direction, int pos) +@deftypefun int history_search_pos (const char *string, int direction, int pos) Search for @var{string} in the history list, starting at @var{pos}, an absolute index into the list. If @var{direction} is negative, the search proceeds backward from @var{pos}, otherwise forward. Returns the absolute @@ -292,41 +302,46 @@ index of the history element where @var{string} was found, or -1 otherwise. The History library can read the history from and write it to a file. This section documents the functions for managing a history file. -@deftypefun int read_history (char *filename) -Add the contents of @var{filename} to the history list, a line at a -time. If @var{filename} is @code{NULL}, then read from -@file{~/.history}. Returns 0 if successful, or errno if not. +@deftypefun int read_history (const char *filename) +Add the contents of @var{filename} to the history list, a line at a time. +If @var{filename} is @code{NULL}, then read from @file{~/.history}. +Returns 0 if successful, or @code{errno} if not. @end deftypefun -@deftypefun int read_history_range (char *filename, int from, int to) +@deftypefun int read_history_range (const char *filename, int from, int to) Read a range of lines from @var{filename}, adding them to the history list. -Start reading at line @var{from} and end at @var{to}. If -@var{from} is zero, start at the beginning. If @var{to} is less than +Start reading at line @var{from} and end at @var{to}. +If @var{from} is zero, start at the beginning. If @var{to} is less than @var{from}, then read until the end of the file. If @var{filename} is @code{NULL}, then read from @file{~/.history}. Returns 0 if successful, or @code{errno} if not. @end deftypefun -@deftypefun int write_history (char *filename) +@deftypefun int write_history (const char *filename) Write the current history to @var{filename}, overwriting @var{filename} -if necessary. If @var{filename} is -@code{NULL}, then write the history list to @file{~/.history}. Values -returned are as in @code{read_history ()}. +if necessary. +If @var{filename} is @code{NULL}, then write the history list to +@file{~/.history}. +Returns 0 on success, or @code{errno} on a read or write error. @end deftypefun -@deftypefun int append_history (int nelements, char *filename) +@deftypefun int append_history (int nelements, const char *filename) Append the last @var{nelements} of the history list to @var{filename}. +If @var{filename} is @code{NULL}, then append to @file{~/.history}. +Returns 0 on success, or @code{errno} on a read or write error. @end deftypefun -@deftypefun int history_truncate_file (char *filename, int nlines) +@deftypefun int history_truncate_file (const char *filename, int nlines) Truncate the history file @var{filename}, leaving only the last @var{nlines} lines. +If @var{filename} is @code{NULL}, then @file{~/.history} is truncated. +Returns 0 on success, or @code{errno} on failure. @end deftypefun @node History Expansion @subsection History Expansion -These functions implement @code{csh}-like history expansion. +These functions implement history expansion. @deftypefun int history_expand (char *string, char **output) Expand @var{string}, placing the result into @var{output}, a pointer @@ -334,7 +349,7 @@ to a string (@pxref{History Interaction}). Returns: @table @code @item 0 If no expansions took place (or, if the only change in -the text was the de-slashifying of the history expansion +the text was the removal of escape characters preceding the history expansion character); @item 1 if expansions did take place; @@ -349,12 +364,7 @@ If an error ocurred in expansion, then @var{output} contains a descriptive error message. @end deftypefun -@deftypefun {char *} history_arg_extract (int first, int last, char *string) -Extract a string segment consisting of the @var{first} through @var{last} -arguments present in @var{string}. Arguments are broken up as in Bash. -@end deftypefun - -@deftypefun {char *} get_history_event (char *string, int *cindex, int qchar) +@deftypefun {char *} get_history_event (const char *string, int *cindex, int qchar) Returns the text of the history event beginning at @var{string} + @var{*cindex}. @var{*cindex} is modified to point to after the event specifier. At function entry, @var{cindex} points to the index into @@ -363,18 +373,24 @@ is a character that is allowed to end the event specification in addition to the ``normal'' terminating characters. @end deftypefun -@deftypefun {char **} history_tokenize (char *string) +@deftypefun {char **} history_tokenize (const char *string) Return an array of tokens parsed out of @var{string}, much as the -shell might. The tokens are split on white space and on the -characters @code{()<>;&|$}, and shell quoting conventions are -obeyed. +shell might. The tokens are split on the characters in the +@var{history_word_delimiters} variable, +and shell quoting conventions are obeyed. +@end deftypefun + +@deftypefun {char *} history_arg_extract (int first, int last, const char *string) +Extract a string segment consisting of the @var{first} through @var{last} +arguments present in @var{string}. Arguments are split using +@code{history_tokenize}. @end deftypefun @node History Variables @section History Variables -This section describes the externally visible variables exported by -the GNU History Library. +This section describes the externally-visible variables exported by +the @sc{gnu} History Library. @deftypevar int history_base The logical offset of the first entry in the history list. @@ -384,13 +400,14 @@ The logical offset of the first entry in the history list. The number of entries currently stored in the history list. @end deftypevar -@deftypevar int max_input_history +@deftypevar int history_max_entries The maximum number of history entries. This must be changed using -@code{stifle_history ()}. +@code{stifle_history()}. @end deftypevar @deftypevar char history_expansion_char -The character that starts a history event. The default is @samp{!}. +The character that introduces a history event. The default is @samp{!}. +Setting this to 0 inhibits history expansion. @end deftypevar @deftypevar char history_subst_char @@ -405,15 +422,20 @@ ignored, suppressing history expansion for the remainder of the line. This is disabled by default. @end deftypevar +@deftypevar {char *} history_word_delimiters +The characters that separate tokens for @code{history_tokenize()}. +The default value is @code{" \t\n()<>;&|"}. +@end deftypevar + @deftypevar {char *} history_no_expand_chars The list of characters which inhibit history expansion if found immediately -following @var{history_expansion_char}. The default is whitespace and -@samp{=}. +following @var{history_expansion_char}. The default is space, tab, newline, +carriage return, and @samp{=}. @end deftypevar @deftypevar {char *} history_search_delimiter_chars The list of additional characters which can delimit a history search -string, in addition to whitespace, @samp{:} and @samp{?} in the case of +string, in addition to space, TAB, @samp{:} and @samp{?} in the case of a substring search. The default is empty. @end deftypevar @@ -422,24 +444,30 @@ If non-zero, single-quoted words are not scanned for the history expansion character. The default value is 0. @end deftypevar -@deftypevar {Function *} history_inhibit_expansion_function +@deftypevar {rl_linebuf_func_t *} history_inhibit_expansion_function This should be set to the address of a function that takes two arguments: -a @code{char *} (@var{string}) and an integer index into that string (@var{i}). +a @code{char *} (@var{string}) +and an @code{int} index into that string (@var{i}). It should return a non-zero value if the history expansion starting at @var{string[i]} should not be performed; zero if the expansion should be done. It is intended for use by applications like Bash that use the history expansion character for additional purposes. -By default, this variable is set to NULL. +By default, this variable is set to @code{NULL}. @end deftypevar @node History Programming Example @section History Programming Example -The following program demonstrates simple use of the GNU History Library. +The following program demonstrates simple use of the @sc{gnu} History Library. @smallexample -main () +#include <stdio.h> +#include <readline/history.h> + +main (argc, argv) + int argc; + char **argv; @{ char line[1024], *t; int len, done = 0; |