Emacs 26.1 New Features (released 2018-06)

By Xah Lee. Date: . Last updated: .

This page is a on-going list of tips and tricks about emacs 26. Emacs 26.1 is released on .

am going thru the emacs 26 feature list and write about them.

2.3 Emacs now supports 24-bit colors on capable text terminals.

electric-quote-chars

3.7 The new user variable 'electric-quote-chars' provides a list of curved quotes for 'electric-quote-mode', allowing user to choose the types of quotes to be used.

3.8 The new user option 'electric-quote-context-sensitive' makes

'electric-quote-mode' context sensitive. If it is non-nil, you can type an ASCII apostrophe to insert an opening or closing quote, depending on context. Emacs will replace the apostrophe by an opening quote character at the beginning of the buffer, the beginning of a line, after a whitespace character, and after an opening parenthesis; and it will replace the apostrophe by a closing quote character in all other cases.

3.9 The new variable 'electric-quote-inhibit-functions' controls when

to disable electric quoting based on context. Major modes can add functions to this list; Emacs will temporarily disable 'electric-quote-mode' whenever any of the functions returns non-nil. This can be used by major modes that derive from 'text-mode' but allow inline code segments, such as 'markdown-mode'.

3.13 The new function 'call-shell-region' executes a command in an

inferior shell with the buffer region as input.

3.37 The new 'list-timers' command lists all active timers in a buffer, where you can cancel them with the 'c' command.

3.38 'switch-to-buffer-preserve-window-point' now defaults to t.

Applications that call 'switch-to-buffer' and want to show the buffer at the position of its point should use 'pop-to-buffer-same-window' in lieu of 'switch-to-buffer'.

3.56 Emacs now supports optional display of line numbers in the buffer. This is similar to what 'linum-mode' provides, but much faster and doesn't usurp the display margin for the line numbers. Customize the buffer-local variable 'display-line-numbers' to activate this optional display. Alternatively, you can use the 'display-line-numbers-mode' minor mode or the global 'global-display-line-numbers-mode'. When using these modes, customize 'display-line-numbers-type' with the same value as you would use with 'display-line-numbers'.

Line numbers are not displayed at all in minibuffer windows and in tooltips, as they are not useful there.

Lisp programs can disable line-number display for a particular screen line by putting the display-line-numbers-disable text property or overlay property on the first character of that screen line. This is intended for add-on packages that need a finer control of the display.

Lisp programs that need to know how much screen estate is used up for line-number display in a window can use the new function line-number-display-width.

linum-mode and all similar packages are henceforth becoming obsolete. Users and developers are encouraged to switch to this new feature instead.


3.45 File name quoting by adding the prefix "/:" is now possible for the

local part of a remote file name. Thus, if you have a directory named "~" on the remote host "foo", you can prevent it from being substituted by a home directory by writing it as "/foo::/~/file".

3.46 The new variable 「maximum-scroll-margin」 allows having effective

settings of 「scroll-margin」 up to half the window size, instead of always restricting the margin to a quarter of the window.

3.47 Emacs can scroll horizontally using mouse, touchpad, and trackbar.

You can enable this by customizing 「mouse-wheel-tilt-scroll」. If you want to reverse the direction of the scroll, customize 「mouse-wheel-flip-direction」.

3.48 The default GnuTLS priority string now includes %DUMBFW.

This is to avoid bad behavior in some firewalls, which causes the connection to be closed by the remote host.

3.49 Emacsclient changes

3.49.1 Emacsclient has a new option '-u' / '–suppress-output'.

This option suppresses display of return values from the server process.

3.49.2 Emacsclient has a new option '-T' / '–tramp'.

This helps with using a local Emacs session as the server for a remote emacsclient. With appropriate setup, one can now set the EDITOR environment variable on a remote machine to emacsclient, and use the local Emacs to edit remote files via Tramp. See the node "(emacs) emacsclient Options" in the user manual for the details.

3.49.3 Emacsclient now accepts command-line options in ALTERNATEEDITOR

and '–alternate-editor'. For example, ALTERNATEEDITOR="emacs -Q -nw". Arguments may be quoted "like this", so that for example an absolute path containing a space may be specified; quote escaping is not supported.

3.50 New user option dig-program-options and extended functionality

for DNS-querying functions nslookup-host, dns-lookup-host, and run-dig. Each function now accepts an optional name server argument interactively (with a prefix argument) and non-interactively.

3.51 describe-key-briefly now ignores mouse movement events.

3.52 The new variable eval-expression-print-maximum-character prevents

large integers from being displayed as characters by 'M-:' and similar commands.

3.53 Two new commands for finding the source code of Emacs Lisp

libraries: find-library-other-window and find-library-other-frame.

3.54 The new variable display-raw-bytes-as-hex allows you to change

the display of raw bytes from octal to hex.

3.55 You can now provide explicit field numbers in format specifiers.

For example, '(format "%2$s %1$s %2$s" "X" "Y")' produces "Y X Y".

3.57 The new user option arabic-shaper-ZWNJ-handling controls how to

handle ZWNJ in Arabic text rendering.

4 Editing Changes in Emacs 26.1

4.1 New variable column-number-indicator-zero-based.

Traditionally, in Column Number mode, the displayed column number counts from zero starting at the left margin of the window. This behavior is now controlled by column-number-indicator-zero-based. If you would prefer for the displayed column number to count from one, you may set this variable to nil. (Behind the scenes, there is now a new mode line construct, '%C', which operates exactly as '%c' does except that it counts from one.)

4.2 New single-line horizontal scrolling mode.

The auto-hscroll-mode variable can now have a new special value, current-line, which causes only the line where the cursor is displayed to be horizontally scrolled when lines are truncated on display and point moves outside the left or right window margin.

4.3 New mode line constructs '%o' and '%q', and user option

mode-line-percent-position. '%o' displays the "degree of travel" of the window through the buffer. Unlike the default '%p', this percentage approaches 100% as the window approaches the end of the buffer. '%q' displays the percentage offsets of both the start and the end of the window, e.g. "5-17%". The new option mode-line-percent-position makes it easier to switch between '%p', '%P', and these new constructs.

4.4 Two new user options list-matching-lines-jump-to-current-line and

list-matching-lines-current-line-face to show the current line highlighted in Occur buffer.

4.5 The occur command can now operate on the region.

4.6 New bindings for query-replace-map.

undo, undo the last replacement; bound to 'u'. undo-all, undo all replacements; bound to 'U'.

4.7 delete-trailing-whitespace deletes whitespace after form feed.

In modes where form feed was treated as a whitespace character, delete-trailing-whitespace would keep lines containing it unchanged. It now deletes whitespace after the last form feed thus behaving the same as in modes where the character is not whitespace.

4.8 Emacs no longer prompts about editing a changed file when the file's

content is unchanged. Instead of only checking the modification time, Emacs now also checks the file's actual content before prompting the user.

4.9 Various casing improvements.

4.9.1 upcase, upcase-region et al. convert title case characters

(such as Dz) into their upper case form (such as DZ).

4.9.2 capitalize, upcase-initials et al. make use of title-case forms

of initial characters (correctly producing for example Džungla instead of incorrect DŽungla).

4.9.3 Characters which turn into multiple ones when cased are correctly handled.

For example, fi ligature is converted to FI when upper cased.

4.9.4 Greek small sigma is correctly handled when at the end of the word.

Strings such as ΌΣΟΣ are now correctly converted to Όσος when capitalized instead of incorrect Όσοσ (compare lowercase sigma at the end of the word).

4.10 Emacs can now auto-save buffers to visited files in a more robust

manner via the new mode auto-save-visited-mode. Unlike auto-save-visited-file-name, this mode uses the normal saving procedure and therefore obeys saving hooks. auto-save-visited-file-name is now obsolete.

4.11 New behavior of mark-defun.

Prefix argument selects that many (or that many more) defuns. Negative prefix arg flips the direction of selection. Also, mark-defun between defuns correctly selects N following defuns (or -N previous for negative arguments). Finally, comments preceding the defun are selected unless they are separated from the defun by a blank line.

4.12 New command replace-buffer-contents.

This command replaces the contents of the accessible portion of the current buffer with the contents of the accessible portion of a different buffer while keeping point, mark, markers, and text properties as intact as possible.

4.13 New commands apropos-local-variable and apropos-local-value.

These are buffer-local versions of apropos-variable and apropos-value, respectively. They show buffer-local variables whose names and values, respectively, match a given pattern.

4.14 More user control of reordering bidirectional text for display.

The two new variables, bidi-paragraph-start-re and bidi-paragraph-separate-re, allow customization of what exactly are paragraphs, for the purposes of bidirectional display.

4.15 New variable x-wait-for-event-timeout.

This controls how long Emacs will wait for updates to the graphical state to take effect (making a frame visible, for example).

5 Changes in Specialized Modes and Packages in Emacs 26.1

5.1 Emacs 26.1 comes with Org v9.1.6.

See the file ORG-NEWS for user-visible changes in Org.

5.2 New function cl-generic-p.

5.3 Dired

5.3.1 You can answer 'all' in dired-do-delete to delete recursively all

remaining directories without more prompts.

5.3.2 Dired supports wildcards in the directory part of the file names.

5.3.3 You can now use '`?`' in dired-do-shell-command.

It gets replaced by the current file name, like ' ? '.

5.3.4 A new option dired-always-read-filesystem defaulting to nil.

If non-nil, buffers visiting files are reverted before they are searched; for instance, in dired-mark-files-containing-regexp a non-nil value of this option means the file is revisited in a temporary buffer; this temporary buffer is the actual buffer searched: the original buffer visiting the file is not modified.

5.3.5 Users can now customize mouse clicks in Dired in a more flexible way.

The new command dired-mouse-find-file can be bound to a mouse click and used to visit files/directories in Dired in the selected window. The new command dired-mouse-find-file-other-frame similarly visits files/directories in another frame. You can write your own commands that invoke dired-mouse-find-file with non-default optional arguments, to tailor the effects of mouse clicks on file names in Dired buffers.

5.3.6 In wdired, when editing files to contain slash characters,

the resulting directories are automatically created. Whether to do this is controlled by the wdired-create-parent-directories variable.

5.3.7 'W' is now bound to browse-url-of-dired-file, and is useful for

viewing HTML files and the like.

5.3.8 New variable dired-clean-confirm-killing-deleted-buffers

controls whether Dired asks to kill buffers visiting deleted files and directories. The default is t, so Dired asks for confirmation, to keep previous behavior.

5.4 html2text is now marked obsolete.

5.5 smerge-refine-regions can refine regions in separate buffers.

5.6 Info menu and index completion uses substring completion by default.

This can be customized via the info-menu category in completion-category-overrides.

5.7 The ancestor buffer is shown by default in 3-way merges.

A new option ediff-show-ancestor and a new toggle ediff-toggle-show-ancestor.

5.8 TeX: Add luatex and xetex as alternatives to pdftex

5.9 Electric-Buffer-menu

5.9.1 Key 'U' is bound to Buffer-menu-unmark-all and key 'M-DEL' is

bound to Buffer-menu-unmark-all-buffers.

5.10 hideshow mode got four key bindings that are analogous to outline

mode bindings: 'C-c @ C-a', 'C-c @ C-t', 'C-c @ C-d', and 'C-c @ C-e'.

5.11 bs

5.11.1 Two new commands bs-unmark-all, bound to 'U', and

bs-unmark-previous, bound to <backspace>.

5.12 Buffer-menu

5.12.1 Two new commands Buffer-menu-unmark-all, bound to 'U' and

Buffer-menu-unmark-all-buffers, bound to 'M-DEL'.

5.13 Checkdoc

5.13.1 checkdoc-arguments-in-order-flag now defaults to nil.

5.14 Gnus

5.14.1 The ~/.newsrc file will now only be saved if the native select

method is an NNTP select method.

5.14.2 A new command for sorting articles by readedness marks has been

added: 'C-c C-s C-m C-m'.

5.14.3 In message-citation-line-format the '%Z' format is now the time

zone name instead of the numeric form. The '%z' format continues to be the numeric form. The new behavior is compatible with format-time-string.

5.15 Ibuffer

5.15.1 New command ibuffer-jump.

5.15.2 New filter commands ibuffer-filter-by-basename,

ibuffer-filter-by-file-extension, ibuffer-filter-by-directory, ibuffer-filter-by-starred-name, ibuffer-filter-by-modified and ibuffer-filter-by-visiting-file; bound respectively to 'b', '.', '//', '/*', '/i' and '/v'.

5.15.3 Two new commands ibuffer-filter-chosen-by-completion

and ibuffer-and-filter, the second bound to '/&'.

5.15.4 The commands ibuffer-pop-filter, ibuffer-pop-filter-group,

ibuffer-or-filter and ibuffer-filter-disable have the alternative bindings '/<up>', '/S-<up>', '/|' and '/DEL', respectively.

5.15.5 The data format specifying filters has been extended to allow

explicit logical 'and', and a more flexible form for logical 'not'. See ibuffer-filtering-qualifiers doc string for full details.

5.15.6 A new command ibuffer-copy-buffername-as-kill; bound

to 'B'.

5.15.7 New command ibuffer-change-marks; bound to '* c'.

5.15.8 A new command ibuffer-mark-by-locked to mark

all locked buffers; bound to '% L'.

5.15.9 A new option ibuffer-locked-char to indicate

locked buffers; Ibuffer shows a new column displaying ibuffer-locked-char for locked buffers.

5.15.10 A new command ibuffer-unmark-all-marks to unmark

all buffers without asking confirmation; bound to 'U'; ibuffer-do-replace-regexp bound to 'r'.

5.15.11 A new command ibuffer-mark-by-content-regexp to mark buffers

whose content matches a regexp; bound to '% g'.

5.15.12 Two new options ibuffer-never-search-content-name and

ibuffer-never-search-content-mode used by ibuffer-mark-by-content-regexp.

5.16 Browse-URL

5.16.1 Support for opening links to man pages in Man or WoMan mode.

5.17 Comint

5.17.1 New user option comint-move-point-for-matching-input to control

where to place point after 'C-c M-r' and 'C-c M-s'.

5.17.2 New user option comint-terminfo-terminal.

This option allows control of the value of the TERM environment variable Emacs puts into the environment of the Comint mode and its derivatives, such as Shell mode and Compilation Shell minor-mode. The default is "dumb", for compatibility with previous behavior.

5.18 Compilation mode

5.18.1 Messages from CMake are now recognized.

5.18.2 The number of errors, warnings, and informational messages is now

displayed in the mode line. These are updated as compilation proceeds.

5.19 Grep

5.19.1 Grep commands will now use GNU grep's '–null' option if

available, which allows distinguishing the filename from contents if they contain colons. This can be controlled by the new custom option grep-use-null-filename-separator.

5.19.2 The grep/rgrep/lgrep functions will now ask about saving files

before running. This is controlled by the grep-save-buffers variable.

5.20 Edebug

5.20.1 Edebug can be prevented from pausing 1 second after reaching a

breakpoint (e.g. with "f" and "o") by customizing the new option edebug-sit-on-break.

5.20.2 New customizable option edebug-max-depth.

This allows you to enlarge the maximum recursion depth when instrumenting code.

5.20.3 'edebug-prin1-to-string' now aliases 'cl-prin1-to-string'.

This means edebug output is affected by variables cl-print-readably and cl-print-compiled. To completely restore the previous printing behavior, use

(fset 'edebug-prin1-to-string #'prin1-to-string)

5.21 Eshell

5.21.1 eshell-input-filters value is now a named function

eshell-input-filter-default, and has a new custom option eshell-input-filter-initial-space to ignore adding commands prefixed with blank space to eshell history.

5.22 EUDC

5.22.1 Backward compatibility support for BBDB versions less than 3

(i.e., BBDB 2.x) is deprecated and will likely be removed in the next major release of Emacs. Users of BBDB 2.x should plan to upgrade to BBDB 3.x.

5.23 eww

5.23.1 New 'M-RET' command for opening a link at point in a new eww buffer.

5.23.2 A new 's' command for switching to another eww buffer via the minibuffer.

5.23.3 The 'o' command (shr-save-contents) has moved to 'O' to avoid collision

with the 'o' command from 'image-map'.

5.23.4 A new command 'C' (eww-toggle-colors) can be used to toggle

whether to use the HTML-specified colors or not. The user can also customize the shr-use-colors variable.

5.23.5 Images that are being loaded are now marked with gray

"placeholder" images of the size specified by the HTML. They are then replaced by the real images asynchronously, which will also now respect width/height HTML specs (unless they specify widths/heights bigger than the current window).

5.23.6 The 'w' command on links is now shr-maybe-probe-and-copy-url.

shr-copy-url now only copies the url at point; users who wish to avoid accidentally accessing remote links may rebind 'w' and 'u' in eww-link-keymap to it.

5.24 Ido

5.24.1 The commands find-alternate-file-other-window,

dired-other-window, dired-other-frame, and display-buffer-other-window are now remapped to Ido equivalents if Ido mode is active.

5.25 Images

5.25.1 Images are automatically scaled before displaying based on the

image-scaling-factor variable (if Emacs supports scaling the images in question).

5.25.2 It's now possible to specify aspect-ratio preserving combinations

of :width/:max-height and :height/:max-width keywords. In either case, the "max" keywords win. (Previously some combinations would, depending on the aspect ratio of the image, just be ignored and in other instances this would lead to the aspect ratio not being preserved.)

5.25.3 Images inserted with insert-image and related functions get a

keymap put into the text properties (or overlays) that span the image. This keymap binds keystrokes for manipulating size and rotation, as well as saving the image to a file. These commands are also available in image-mode.

5.25.4 A new library for creating and manipulating SVG images has been

added. See the "(elisp) SVG Images" section in the ELisp reference manual for details.

5.25.5 New setf-able function to access and set image parameters is

provided: image-property.

5.25.6 New commands image-scroll-left and image-scroll-right

for image-mode that complement image-scroll-up and image-scroll-down: they have the same prefix arg behavior and stop at image boundaries.

5.26 Image-Dired

5.26.1 Now provides a minor mode image-dired-minor-mode which replaces

the function image-dired-setup-dired-keybindings.

5.26.2 Thumbnail generation is now asynchronous.

The number of concurrent processes is limited by the variable image-dired-queue-active-limit.

5.26.3 image-dired-thumbnail-storage has a new option standard-large

for generating 256x256 thumbnails according to the Thumbnail Managing Standard.

5.26.4 Inherits movement keys from image-mode for viewing full images.

This includes the usual char, line, and page movement commands.

5.26.5 All the -options types have been changed to argument lists

instead of shell command strings. This change affects image-dired-cmd-create-thumbnail-options, image-dired-cmd-create-temp-image-options, image-dired-cmd-rotate-thumbnail-options, image-dired-cmd-rotate-original-options, image-dired-cmd-write-exif-data-options, image-dired-cmd-read-exif-data-options, and introduces image-dired-cmd-pngnq-options, image-dired-cmd-pngcrush-options, image-dired-cmd-create-standard-thumbnail-options.

5.26.6 Recognizes more tools by default, including pngnq-s9 and OptiPNG.

5.26.7 find-file and related commands now work on thumbnails and

displayed images, providing a default argument of the original file name via an addition to file-name-at-point-functions.

5.27 The default Info-default-directory-list no longer checks some obsolete

directory suffixes (gnu, gnu/lib, gnu/lib/emacs, emacs, lib, lib/emacs) when searching for info directories.

5.28 The commands that add ChangeLog entries now prefer a VCS root directory

for the ChangeLog file, if none already exists. Customize change-log-directory-files to nil for the old behavior.

5.29 Support for non-string values of time-stamp-format has been removed.

5.30 Message

5.30.1 message-use-idna now defaults to t (because Emacs comes with

built-in IDNA support now).

5.30.2 When sending HTML messages with embedded images, and you have

exiftool installed, and you rotate images with EXIF data (i.e., JPEGs), the rotational information will be inserted into the outgoing image in the message. (The original image will not have its orientation affected.)

5.30.3 The message-valid-fqdn-regexp variable has been removed, since

there are now top-level domains added all the time. Message will no longer warn about sending emails to top-level domains it hasn't heard about.

5.30.4 message-beginning-of-line (bound to 'C-a') understands folded headers.

In visual-line-mode it will look for the true beginning of a header while in non-visual-line-mode it will move the point to the indented header's value.

5.31 Package

5.31.1 The new variable package-gnupghome-dir has been added to control

where the GnuPG home directory (used for signature verification) is located and whether GnuPG's option '–homedir' is used or not.

5.31.2 Deleting a package no longer respects delete-by-moving-to-trash.

5.32 Python

5.32.1 The new variable python-indent-def-block-scale has been added.

It controls the depth of indentation of arguments inside multi-line function signatures.

5.33 Tramp

5.33.1 The method part of remote file names is mandatory now.

A valid remote file name starts with "/method:host:" or "/method:user@host:".

5.33.2 The new pseudo method "-" is a marker for the default method.

"/-::" is the shortest remote file name then.

5.33.3 The command tramp-change-syntax allows you to choose an

alternative remote file name syntax.

5.33.4 New connection method "sg", which supports editing files under a

different group ID.

5.33.5 New connection method "doas" for OpenBSD hosts.

5.33.6 New connection method "gdrive", which allows access to Google

Drive onsite repositories.

5.33.7 Gateway methods in Tramp have been removed.

Instead, the Tramp manual documents how to configure ssh and PuTTY accordingly.

5.33.8 Setting the "ENV" environment variable in

tramp-remote-process-environment enables reading of shell initialization files.

5.33.9 Tramp is able now to send SIGINT to remote asynchronous processes.

5.33.10 Variable tramp-completion-mode is obsoleted.

5.34 auto-revert-use-notify is set back to t in global-auto-revert-mode.

5.35 JS mode

5.35.1 JS mode now sets comment-multi-line to t.

5.35.2 New variable js-indent-align-list-continuation, when set to nil,

will not align continuations of bracketed lists, but will indent them by the fixed width js-indent-level.

5.36 CSS mode

5.36.1 Support for completing attribute values, at-rules, bang-rules,

HTML tags, classes and IDs using the completion-at-point command. Completion candidates for HTML classes and IDs are retrieved from open HTML mode buffers.

5.36.2 CSS mode now binds 'C-h S' to a function that will show

information about a CSS construct (an at-rule, property, pseudo-class, pseudo-element, with the default being guessed from context). By default the information is looked up on the Mozilla Developer Network, but this can be customized using css-lookup-url-format.

5.36.3 CSS colors are fontified using the color they represent as the

background. For instance, #ff0000 would be fontified with a red background.

5.37 Emacs now supports character name escape sequences in character and

string literals. The syntax variants '\N{character name}' and '\N{U+code}' are supported.

5.38 Prog mode has some support for multi-mode indentation.

This allows better indentation support in modes that support multiple programming languages in the same buffer, like literate programming environments or ANTLR programs with embedded Python code.

A major mode can provide indentation context for a sub-mode. To support this, modes should use prog-first-column instead of a literal zero and avoid calling widen in their indentation functions. See the node "(elisp) Mode-Specific Indent" in the ELisp manual for more details.

5.39 ERC

5.39.1 New variable erc-default-port-tls used to connect to TLS IRC

servers.

5.40 URL

5.40.1 The new function url-cookie-delete-cookie can be used to

programmatically delete all cookies, or cookies from a specific domain.

5.40.2 url-retrieve-synchronously now takes an optional timeout parameter.

5.40.3 The URL package now supports HTTPS over proxies supporting CONNECT.

5.40.4 url-user-agent now defaults to 'default', and the User-Agent

string is computed dynamically based on url-privacy-level.

5.41 VC and related modes

5.41.1 vc-dir-mode now binds vc-log-outgoing to 'O'; and has various

branch-related commands on a keymap bound to 'B'.

5.41.2 vc-region-history is now bound to 'C-x v h', replacing the older

vc-insert-headers binding.

5.41.3 New user option vc-git-print-log-follow to follow renames in Git logs

for a single file.

5.42 CC mode

5.42.1 Opening a .h file will turn C or C++ mode depending on language used.

This is done with the help of the 'c-or-c++-mode' function, which analyzes buffer contents to infer whether it's a C or C++ source file.

5.43 New option cpp-message-min-time-interval to allow user control

of progress messages in cpp.el.

5.44 New DNS mode command 'dns-mode-ipv6-to-nibbles' to convert IPv6 addresses

to a format suitable for reverse lookup zone files.

5.45 Ispell

5.45.1 Enchant is now supported as a spell-checker.

Enchant is a meta-spell-checker that uses providers such as Hunspell to do the actual checking. With it, users can use spell-checkers not directly supported by Emacs, such as Voikko, Hspell and AppleSpell, more easily share personal word-lists with other programs, and configure different spelling-checkers for different languages. (Version 2.1.0 or later of Enchant is required.)

5.46 Flymake

5.46.1 Flymake has been completely redesigned

Flymake now annotates arbitrary buffer regions, not just lines. It supports arbitrary diagnostic types, not just errors and warnings (see variable flymake-diagnostic-types-alist).

It also supports multiple simultaneous backends, meaning that you can check your buffer from different perspectives (see variable flymake-diagnostic-functions). Backends for Emacs Lisp mode are provided.

The old Flymake behavior is preserved in the so-called "legacy backend", which has been updated to benefit from the new UI features.

5.47 Term

5.47.1 term-char-mode now makes its buffer read-only.

The buffer is made read-only to prevent changes from being made by anything other than the process filter; and movements of point away from the process mark are counter-acted so that the cursor is in the correct position after each command. This is needed to avoid states which are inconsistent with the state of the terminal understood by the inferior process.

New user options term-char-mode-buffer-read-only and term-char-mode-point-at-process-mark control these behaviors, and are non-nil by default. Customize these options to nil if you want the previous behavior.

5.48 Xref

5.48.1 When an xref buffer is needed, 'TAB' quits and jumps to an xref.

A new command xref-quit-and-goto-xref, bound to 'TAB' in xref buffers, quits the window before jumping to the destination. In many situations, the intended window configuration is restored, just as if the xref buffer hadn't been necessary in the first place.

6 New Modes and Packages in Emacs 26.1

6.1 New Elisp data-structure library radix-tree.

6.2 New library 'xdg' with utilities for some XDG standards and specs.

6.3 HTML

6.3.1 A new submode of html-mode, mhtml-mode, is now the default

mode for *.html files. This mode handles indentation, fontification, and commenting for embedded JavaScript and CSS.

6.4 New mode conf-toml-mode is a sub-mode of conf-mode, specialized

for editing TOML files.

6.5 New mode conf-desktop-mode is a sub-mode of conf-unix-mode,

specialized for editing freedesktop.org desktop entries.

6.6 New minor mode pixel-scroll-mode provides smooth pixel-level scrolling.

6.7 New major mode less-css-mode (a minor variant of css-mode) for

editing Less files.

6.8 New package auth-source-pass integrates auth-source with the

password manager password-store (http://passwordstore.org).

7 Incompatible Lisp Changes in Emacs 26.1

7.1 password-data is now a hash-table so that password-read can use

any object for the 'key' argument.

7.2 Command dired-mark-extension now automatically prepends a '.' to the

extension when not present. The new command dired-mark-suffix behaves similarly but it doesn't prepend a '.'.

7.3 Certain cond/pcase/cl-case forms are now compiled using a faster jump

table implementation. This uses a new bytecode op 'switch', which isn't compatible with previous Emacs versions. This functionality can be disabled by setting byte-compile-cond-use-jump-table to nil.

7.4 If comment-auto-fill-only-comments is non-nil, auto-fill-function

is now called only if either no comment syntax is defined for the current buffer or the self-insertion takes place within a comment.

7.5 The alist ucs-names is now a hash table.

7.6 if-let and when-let now support binding lists as defined by the

SRFI-2 (Scheme Request for Implementation 2).

7.7 'C-up', 'C-down', 'C-left' and 'C-right' are now defined in term

mode to send the same escape sequences that xterm does. This makes things like forward-word in readline work.

7.8 Customizable variable query-replace-from-to-separator

now doesn't propertize the string value of the separator. Instead, text properties are added by query-replace-read-from. Additionally, the new nil value restores pre-24.5 behavior of not providing replacement pairs via the history.

7.9 Some obsolete functions, variables, and faces have been removed:

7.9.1 make-variable-frame-local. Variables cannot be frame-local any more.

7.9.2 From subr.el: window-dot, set-window-dot, read-input,

show-buffer, eval-current-buffer, string-to-int.

7.9.3 icomplete-prospects-length.

7.9.4 All the default-FOO variables that hold the default value of the

FOO variable. Use default-value and setq-default to access and change FOO, respectively. The exhaustive list of removed variables is: default-mode-line-format, default-header-line-format, default-line-spacing, default-abbrev-mode, default-ctl-arrow, default-truncate-lines, default-left-margin, default-tab-width, default-case-fold-search, default-left-margin-width, default-right-margin-width, default-left-fringe-width, default-right-fringe-width, default-fringes-outside-margins, default-scroll-bar-width, default-vertical-scroll-bar, default-indicate-empty-lines, default-indicate-buffer-boundaries, default-fringe-indicator-alist, default-fringe-cursor-alist, default-scroll-up-aggressively, default-scroll-down-aggressively, default-fill-column, default-cursor-type, default-cursor-in-non-selected-windows, default-buffer-file-coding-system, default-major-mode, and default-enable-multibyte-characters.

7.9.5 Many variables obsoleted in 22.1 referring to face symbols.

7.10 The variable text-quoting-style is now a customizable option. It

controls whether to and how to translate ASCII quotes in messages and help output. Its possible values and their semantics remain unchanged from Emacs 25. In particular, when this variable's value is grave, all quotes in formats are output as-is.

7.11 Functions like check-declare-file and check-declare-directory

now generate less chatter and more-compact diagnostics. The auxiliary function check-declare-errmsg has been removed.

7.12 The regular expression character class '[:blank:]' now matches

Unicode horizontal whitespace as defined in the Unicode Technical Standard #18. If you only want to match space and tab, use '[ \t]' instead.

7.13 min and max no longer round their results.

Formerly, they returned a floating-point value if any argument was floating-point, which was sometimes numerically incorrect. For example, on a 64-bit host (max 1e16 10000000000000001) now returns its second argument instead of its first.

7.14 The variable old-style-backquotes has been made internal and

renamed to 'lread–old-style-backquotes'. No user code should use this variable.

7.15 default-file-name-coding-system now defaults to a coding system

that does not process CRLF. For example, it defaults to 'utf-8-unix' instead of to 'utf-8'. Before this change, Emacs would sometimes mishandle file names containing these control characters.

7.16 file-attributes, file-symlink-p and make-symbolic-link no

longer quietly mutate the target of a local symbolic link, so that Emacs can access and copy them reliably regardless of their contents. The following changes are involved.

7.16.1 file-attributes and file-symlink-p no longer prepend "/:" to

symbolic links whose targets begin with "/" and contain ":". For example, if a symbolic link "x" has a target "y:z:", '(file-symlink-p "x")' now returns "/y:z:" rather than ":/y:z:".

7.16.2 make-symbolic-link no longer looks for file name handlers of

target when creating a symbolic link. For example, '(make-symbolic-link "/y:z:" "x")' now creates a symbolic link to "/y:z:" instead of failing.

7.16.3 make-symbolic-link removes the remote part of a link target if

target and newname have the same remote part. For example, '(make-symbolic-link "/x:y:a" "/x:y:b")' creates a link with the literal string "a"; and '(make-symbolic-link "/x:y:a" "/x:z:b")' creates a link with the literal string "/x:y:a" instead of failing.

7.16.4 make-symbolic-link now expands a link target with leading "~"

only when the optional third arg is an integer, as when invoked interactively. For example, '(make-symbolic-link "~y" "x")' now creates a link with target the literal string "~y"; to get the old behavior, use '(make-symbolic-link (expand-file-name "~y") "x")'. To avoid this expansion in interactive use, you can now prefix the link target with ":". For example, '(make-symbolic-link ":~y" "x" 1)' now creates a link to literal "~y".

7.17 file-truename returns a quoted file name if the target of a

symbolic link has remote file name syntax.

7.18 Module functions are now implemented slightly differently; in

particular, the function 'internal–module-call' has been removed. Code that depends on undocumented internals of the module system might break.

7.19 The argument LOCKNAME of write-region is propagated to file name

handlers now.

7.20 When built against recent versions of GTK+, Emacs always uses

gtkwindowmove for moving frames and ignores the value of the variable x-gtk-use-window-move. The variable is now obsolete.

7.21 Several functions that create or rename files now treat their

destination argument specially only when it is a directory name, i.e., when it ends in '/' on GNU and other POSIX-like systems. When the destination argument D of one of these functions is an existing directory and the intent is to act on an entry in that directory, D should now be a directory name. For example, (rename-file "e" "f/") renames to 'f/e'. Although this formerly happened sometimes even when D was not a directory name, as in (rename-file "e" "f") where 'f' happened to be a directory, the old behavior often contradicted the documentation and had inherent races that led to security holes. A call like (rename-file C D) that used the old, undocumented behavior can be written as (rename-file C (file-name-as-directory D)), a formulation portable to both older and newer versions of Emacs. Affected functions include add-name-to-file, copy-directory, copy-file, format-write-file, gnus-copy-file, make-symbolic-link, rename-file, thumbs-rename-images, and write-file.

7.22 The list returned by overlays-at is now in decreasing priority order.

The documentation of this function always said the order should be that of decreasing priority, if the 2nd argument of the function is non-nil, but the code returned the list in the increasing order of priority instead. Now the code does what the documentation says it should do.

7.23 format now avoids allocating a new string in more cases.

format was previously documented to return a newly-allocated string, but this documentation was not correct, as (eq x (format x)) returned t when x was the empty string. format is no longer documented to return a newly-allocated string, and the implementation now takes advantage of the doc change to avoid making copies of strings in common cases like (format "foo") and (format "%s" "foo").

7.24 The function eldoc-message now accepts a single argument.

Programs that called it with multiple arguments before should pass them through format first. Even that is discouraged: for ElDoc support, you should set eldoc-documentation-function instead of calling eldoc-message directly.

7.25 Using '&rest' or '&optional' incorrectly is now an error.

For example giving '&optional' without a following variable, or passing '&optional' multiple times:

(defun foo (&optional &rest x)) (defun bar (&optional &optional x))

Previously, Emacs would just ignore the extra keyword, or give incorrect results in certain cases.

7.26 The pinentry.el library has been removed.

That package (and the corresponding change in GnuPG and pinentry) was intended to provide a way to input passphrase through Emacs with GnuPG 2.0. However, the change to support that was only implemented in GnuPG >= 2.1 and didn't get backported to GnuPG 2.0. And with GnuPG 2.1 and later, pinentry.el is not needed at all. So the library was useless, and we removed it. GnuPG 2.0 is no longer supported by the upstream project.

To adapt to the change, you may need to set epa-pinentry-mode to the symbol loopback. Alternatively, leave epa-pinentry-mode at its default value of nil, and remove the allow-emacs-pinentry setting from your 'gpg-agent.conf' configuration file, usually found in the '~/.gnupg' directory.

Note that previously, it was said that passphrase input through minibuffer would be much less secure than other graphical pinentry programs. However, these days the difference is insignificant: the read-password function sufficiently protects input from leakage to message logs. Emacs still doesn't use secure memory to protect passphrases, but it was also removed from other pinentry programs as the attack is unrealistic on modern computer systems which don't utilize swap memory usually.

7.27 The function display-buffer-in-major-side-window no longer exists.

It has been renamed as internal function 'window–make-major-side-window', however applications should instead call display-buffer-in-side-window (passing the SIDE and SLOT parameters as elements of ALIST). This approach is backwards-compatible with versions of Emacs in which the old function exists. See the node "Displaying Buffers in Side Windows" in the ELisp manual for more details.

8 Lisp Changes in Emacs 26.1

8.1 The function assoc now takes an optional third argument TESTFN.

This argument, when non-nil, is used for comparison instead of equal.

8.2 New optional argument TESTFN in alist-get, map-elt and map-put.

If non-nil, the argument specifies a function to use for comparison, instead of, respectively, assq and eql.

8.3 New function seq-set-equal-p to check if SEQUENCE1 and SEQUENCE2

contain the same elements, regardless of the order.

8.4 The new function mapbacktrace applies a function to all frames of

the current stack trace.

8.5 The new function file-name-case-insensitive-p tests whether a

given file is on a case-insensitive filesystem.

8.6 Several accessors for the value returned by file-attributes

have been added. They are: file-attribute-type, file-attribute-link-number, file-attribute-user-id, file-attribute-group-id, file-attribute-access-time, file-attribute-modification-time, file-attribute-status-change-time, file-attribute-size, file-attribute-modes, file-attribute-inode-number, file-attribute-device-number and file-attribute-collect.

8.7 The new function buffer-hash computes a fast, non-consing hash of

a buffer's contents.

8.8 interrupt-process now consults the list interrupt-process-functions,

to determine which function has to be called in order to deliver the SIGINT signal. This allows Tramp to send the SIGINT signal to remote asynchronous processes. The hitherto existing implementation has been moved to internal-default-interrupt-process.

8.9 The new function read-multiple-choice prompts for multiple-choice

questions, with a handy way to display help texts.

8.10 comment-indent-function values may now return a cons to specify a

range of indentation.

8.11 New optional argument TEXT in make-temp-file.

8.12 New function define-symbol-prop.

8.13 New function secure-hash-algorithms to list the algorithms that

secure-hash supports. See the node "(elisp) Checksum/Hash" in the ELisp manual for details.

8.14 Emacs now exposes the GnuTLS cryptographic API with the functions

gnutls-macs and gnutls-hash-mac; gnutls-digests and gnutls-hash-digest; gnutls-ciphers and gnutls-symmetric-encrypt and gnutls-symmetric-decrypt. See the node "(elisp) GnuTLS Cryptography" in the ELisp manual for details.

8.15 The function gnutls-available-p now returns a list of capabilities

supported by the GnuTLS library used by Emacs.

8.16 Emacs now supports records for user-defined types, via the new

functions make-record, record, and recordp. Records are now used internally to represent cl-defstruct and defclass instances, for example.

If your program defines new record types, you should use package-naming conventions for naming those types. This is so any potential conflicts with other types are avoided.

8.17 save-some-buffers now uses save-some-buffers-default-predicate

to decide which buffers to ask about, if the PRED argument is nil. The default value of save-some-buffers-default-predicate is nil, which means ask about all file-visiting buffers.

8.18 string-(to|as|make)-(uni|multi)byte are now declared obsolete.

8.19 New variable while-no-input-ignore-events which allow

setting which special events while-no-input should ignore. It is a list of symbols.

8.20 New function undo-amalgamate-change-group to get rid of

undo-boundaries between two states.

8.21 New var definition-prefixes is a hash table mapping prefixes to

the files where corresponding definitions can be found. This can be used to fetch definitions that are not yet loaded, for example for 'C-h f'.

8.22 New var syntax-ppss-table to control the syntax-table used in

syntax-ppss.

8.23 define-derived-mode can now specify an :after-hook form, which

gets evaluated after the new mode's hook has run. This can be used to incorporate configuration changes made in the mode hook into the mode's setup.

8.24 Autoload files are now generated without timestamps.

Set autoload-timestamps to a non-nil value to get timestamps in autoload files.

8.25 gnutls-boot now takes a parameter ':complete-negotiation' that

says that negotiation should complete even on non-blocking sockets.

8.26 There is now a new variable flyspell-sort-corrections-function

that allows changing the way corrections are sorted.

8.27 The new command fortune-message has been added, which displays

fortunes in the echo area.

8.28 New function func-arity returns information about the argument list

of an arbitrary function. This generalizes subr-arity for functions that are not built-in primitives. We recommend using this new function instead of subr-arity.

8.29 New function region-bounds can be used in the interactive spec

to provide region boundaries (for rectangular regions more than one) to an interactively callable function as a single argument instead of two separate arguments region-beginning and region-end.

8.30 parse-partial-sexp state has a new element. Element 10 is

non-nil when the last character scanned might be the first character of a two character construct, i.e., a comment delimiter or escaped character. Its value is the syntax of that last character.

8.31 parse-partial-sexps state, element 9, has now been confirmed as

permanent and documented, and may be used by Lisp programs. Its value is a list of currently open parenthesis positions, starting with the outermost parenthesis.

8.32 read-color will now display the color names using the color itself

as the background color.

8.33 The function redirect-debugging-output now works on platforms

other than GNU/Linux.

8.34 The new function string-version-lessp compares strings by

interpreting consecutive runs of numerical characters as numbers, and compares their numerical values. According to this predicate, "foo2.png" is smaller than "foo12.png".

8.35 Numeric comparisons and logb no longer return incorrect answers

due to internal rounding errors. For example, '(< most-positive-fixnum (+ 1.0 most-positive-fixnum))' now correctly returns t on 64-bit hosts.

8.36 The functions ffloor, fceiling, ftruncate and fround now

accept only floating-point arguments, as per their documentation. Formerly, they quietly accepted integer arguments and sometimes returned nonsensical answers, e.g., '(< N (ffloor N))' could return t.

8.37 On hosts like GNU/Linux x86-64 where a 'long double' fraction

contains at least EMACSINTWIDTH - 3 bits, format no longer returns incorrect answers due to internal rounding errors when formatting Emacs integers with '%e', '%f', or '%g' conversions. For example, on these hosts '(eql N (string-to-number (format "%.0f" N)))' now returns t for all Emacs integers N.

8.38 Calls that accept floating-point integers (for use on hosts with

limited integer range) now signal an error if arguments are not integral. For example '(decode-char 'ascii 0.5)' now signals an error.

8.39 Functions string-trim-left, string-trim-right and string-trim

now accept optional arguments which specify the regexp of a substring to trim.

8.40 The new function char-from-name converts a Unicode name string

to the corresponding character code.

8.41 New functions sxhash-eq and sxhash-eql return hash codes of a

Lisp object suitable for use with eq and eql correspondingly. If two objects are eq (eql), then the result of sxhash-eq (sxhash-eql) on them will be the same.

8.42 Function sxhash has been renamed to sxhash-equal for

consistency with the new functions. For compatibility, sxhash remains as an alias to sxhash-equal.

8.43 make-hash-table now defaults to a rehash threshold of 0.8125

instead of 0.8, to avoid rounding glitches.

8.44 New function add-variable-watcher can be used to call a function

when a symbol's value is changed. This is used to implement the new debugger command debug-on-variable-change.

8.45 New variable print-escape-control-characters causes 'prin1' and

print to output control characters as backslash sequences.

8.46 Time conversion functions that accept a time zone rule argument now

allow it to be OFFSET or a list (OFFSET ABBR), where the integer OFFSET is a count of seconds east of Universal Time, and the string ABBR is a time zone abbreviation. The affected functions are current-time-string, current-time-zone, decode-time, format-time-string, and set-time-zone-rule.

8.47 format-time-string now formats '%q' to the calendar quarter.

8.48 New built-in function mapcan.

It avoids unnecessary consing (and garbage collection).

8.49 car and cdr compositions cXXXr and cXXXXr are now part of Elisp.

8.50 gensym is now part of Elisp.

8.51 Low-level list functions like length and member now do a better

job of signaling list cycles instead of looping indefinitely.

8.52 The new functions make-nearby-temp-file and temporary-file-directory

can be used for creation of temporary files on remote or mounted directories.

8.53 On GNU platforms when operating on a local file, file-attributes

no longer suffers from a race when called while another process is altering the filesystem. On non-GNU platforms file-attributes attempts to detect the race, and returns nil if it does so.

8.54 The new function file-local-name can be used to specify arguments

of remote processes.

8.55 The new functions file-name-quote, file-name-unquote and

file-name-quoted-p can be used to quote / unquote file names with the prefix "/:".

8.56 The new error file-missing, a subcategory of file-error, is now

signaled instead of file-error if a file operation acts on a file that does not exist.

8.57 The function delete-directory no longer signals an error when

operating recursively and when some other process deletes the directory or its files before delete-directory gets to them.

8.58 New error type user-search-failed like search-failed but

avoids debugger like user-error.

8.59 The function line-number-at-pos now takes a second optional

argument absolute. If this parameter is nil, the default, this function keeps on returning the line number taking potential narrowing into account. If this parameter is non-nil, the function ignores narrowing and returns the absolute line number.

8.60 The function color-distance now takes a second optional argument

metric. When non-nil, it should be a function of two arguments that accepts two colors and returns a number.

8.61 Changes in Frame and Window Handling

8.61.1 Resizing a frame no longer runs window-configuration-change-hook.

window-size-change-functions should be used instead.

8.61.2 The new function frame-size-changed-p can tell whether a frame has

been resized since the last time window-size-change-functions has been run.

8.61.3 The function frame-geometry now also returns the width of a

frame's outer border.

8.61.4 New frame parameters and changed semantics for older ones:

  1. z-group positions a frame above or below all others.
  2. min-width and min-height specify the absolute minimum size of a

    frame.

  3. parent-frame makes a frame the child frame of another Emacs

    frame. The section "(elisp) Child Frames" in the ELisp manual describes the intrinsics of that relationship.

  4. delete-before triggers deletion of one frame before that of

    another.

  5. mouse-wheel-frame specifies another frame whose windows shall be

    scrolled instead.

  6. no-other-frame has next-frame and previous-frame skip this

    frame.

  7. skip-taskbar removes a frame's icon from the taskbar and has

    'Alt-<TAB>' skip this frame.

  8. no-focus-on-map avoids that a frame gets input focus when mapped.
  9. no-accept-focus means that a frame does not want to get input

    focus via the mouse.

  10. undecorated removes the window manager decorations from a frame.
  11. override-redirect tells the window manager to disregard this

    frame.

  12. width and height now allow the specification of pixel values

    and ratios.

  13. left and top now allow the specification of ratios.
  14. keep-ratio preserves size and position of child frames when their

    parent frame is resized.

  15. no-special-glyphs suppresses display of truncation and

    continuation glyphs in a frame.

  16. auto-hide-function and minibuffer-exit handle auto hiding of

    frames and exiting from minibuffer individually.

  17. fit-frame-to-buffer-margins and fit-frame-to-buffer-sizes

    handle fitting a frame to its buffer individually.

  18. drag-internal-border, drag-with-header-line,

    drag-with-mode-line, snap-width, top-visible and bottom-visible allow dragging and resizing frames with the mouse.

  19. minibuffer is now set to the default minibuffer window when

    initially specified as nil and is not reset to nil when initially specifying a minibuffer window.

8.61.5 The new function frame-list-z-order returns a list of all frames

in Z (stacking) order.

8.61.6 The function x-focus-frame optionally tries to not activate its

frame.

8.61.7 The variable focus-follows-mouse has a third meaningful value

auto-raise to indicate that the window manager automatically raises a frame when the mouse pointer enters it.

8.61.8 The new function frame-restack puts a frame above or below

another on the display.

8.61.9 The new face internal-border specifies the background of a frame's

internal border.

8.61.10 The NORECORD argument of select-window now has a meaningful value

mark-for-redisplay which is like any other non-nil value but marks WINDOW for redisplay.

8.61.11 Support for side windows is now official. The display action

function display-buffer-in-side-window will display its buffer in a side window. Functions for toggling all side windows on a frame, changing and reversing the layout of side windows and returning the main (major non-side) window of a frame are provided. For details consult the section "(elisp) Side Windows" in the ELisp manual.

8.61.12 Support for atomic windows - rectangular compositions of windows

treated by split-window, delete-window and delete-other-windows like a single live window - is now official. For details consult the section "(elisp) Atomic Windows" in the ELisp manual.

8.61.13 New display-buffer alist entry window-parameters allows the

assignment of window parameters to the window used for displaying the buffer.

8.61.14 New function display-buffer-reuse-mode-window is an action function

suitable for use in display-buffer-alist. For example, to avoid creating a new window when opening man pages when there's already one, use

(add-to-list 'display-buffer-alist '("\\`\\*Man .*\\*\\'" . (display-buffer-reuse-mode-window (inhibit-same-window . nil) (mode . Man-mode))))

8.61.15 New window parameter no-delete-other-windows prevents that

its window gets deleted by delete-other-windows.

8.61.16 New window parameters mode-line-format and header-line-format

allow the buffer-local formats for this window to be overridden.

8.61.17 New command window-swap-states swaps the states of two live

windows.

8.61.18 New functions window-pixel-width-before-size-change and

window-pixel-height-before-size-change support detecting which window changed size when window-size-change-functions are run.

8.61.19 The new function window-lines-pixel-dimensions returns the pixel

dimensions of a window's text lines.

8.61.20 The new function window-largest-empty-rectangle returns the

dimensions of the largest rectangular area not occupying any text in a window's body.

8.61.21 The semantics of mouse-autoselect-window has changed slightly.

For details see the section "(elisp) Mouse Window Auto-selection" in the ELisp manual.

8.61.22 select-frame-by-name now may return a frame on another display

if it does not find a suitable one on the current display.

8.62 tcl-auto-fill-mode is now declared obsolete. Its functionality

can be replicated simply by setting comment-auto-fill-only-comments.

8.63 New pcase pattern rx to match against an rx-style regular expression.

For details, see the doc string of 'rx–pcase-macroexpander'.

8.64 New functions to set region from secondary selection and vice versa.

The new functions secondary-selection-to-region and secondary-selection-from-region let you set the beginning and the end of the region from those of the secondary selection and vice versa.

8.65 New function lgstring-remove-glyph can be used to modify a

gstring returned by the underlying layout engine (e.g. m17n-flt, uniscribe).

9 Changes in Emacs 26.1 on Non-Free Operating Systems

9.1 Intercepting hotkeys on Windows 7 and later now works better.

The new keyboard hooking code properly grabs system hotkeys such as 'Win-*' and Alt-TAB, in a way that Emacs can get at them before the system. This makes the 'w32-register-hot-key' functionality work again on all versions of MS-Windows starting with Windows 7. On Windows NT and later you can now register any hotkey combination. (On Windows 9X, the previous limitations, spelled out in the Emacs manual, still apply.)

9.2 convert-standard-filename no longer mirrors slashes on MS-Windows.

Previously, on MS-Windows this function converted slash characters in file names into backslashes. It no longer does that. If your Lisp program used convert-standard-filename to prepare file names to be passed to subprocesses (which is not the recommended usage of that function), you will now have to mirror slashes in your application code. One possible way is this:

(let ((start 0)) (while (string-match "/" file-name start) (aset file-name (match-beginning 0) ?\\) (setq start (match-end 0))))

9.3 GUI sessions on MS-Windows now treat SIGINT like Posix platforms do.

The effect of delivering a Ctrl-C (SIGINT) signal to a GUI Emacs on MS-Windows is now the same as on Posix platforms – Emacs saves the session and exits. In particular, this will happen if you start emacs.exe from the Windows shell, then type Ctrl-C into that shell's window.

9.4 signal-process supports SIGTRAP on Windows XP and later.

The kill emulation on Windows now maps SIGTRAP to a call to the DebugBreakProcess API. This causes the receiving process to break execution and return control to the debugger. If no debugger is attached to the receiving process, the call is typically ignored. This is in contrast to the default action on POSIX Systems, where it causes the receiving process to terminate with a core dump if no debugger has been attached to it.

9.5 set-mouse-position and set-mouse-absolute-pixel-position work

on macOS.

9.6 Emacs can now be run as a GUI application from the command line on

macOS.

9.7 ns-appearance and ns-transparent-titlebar change the appearance

of frame decorations on macOS 10.9+.

9.8 ns-use-thin-smoothing enables thin font smoothing on macOS 10.8+.

9.9 process-attributes on Darwin systems now returns more information.

9.10 Mousewheel and trackpad scrolling on macOS 10.7+ now behaves more

like the macOS default. The new variables ns-mwheel-line-height, ns-use-mwheel-acceleration and ns-use-mwheel-momentum can be used to customize the behavior.

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