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+*terminal.txt* For Vim version 8.1. Last change: 2019 Feb 03
+
+
+ VIM REFERENCE MANUAL by Bram Moolenaar
+
+
+Terminal window support *terminal* *terminal-window*
+
+
+The terminal feature is optional, use this to check if your Vim has it: >
+ echo has('terminal')
+If the result is "1" you have it.
+
+
+1. Basic use |terminal-use|
+ Typing |terminal-typing|
+ Size and color |terminal-size-color|
+ Syntax |:terminal|
+ Resizing |terminal-resizing|
+ Terminal Modes |Terminal-mode|
+ Cursor style |terminal-cursor-style|
+ Session |terminal-session|
+ Special keys |terminal-special-keys|
+ Unix |terminal-unix|
+ MS-Windows |terminal-ms-windows|
+2. Terminal communication |terminal-communication|
+ Vim to job: term_sendkeys() |terminal-to-job|
+ Job to Vim: JSON API |terminal-api|
+ Using the client-server feature |terminal-client-server|
+3. Remote testing |terminal-testing|
+4. Diffing screen dumps |terminal-diff|
+ Writing a screen dump test for Vim |terminal-dumptest|
+ Creating a screen dump |terminal-screendump|
+ Comparing screen dumps |terminal-diffscreendump|
+5. Debugging |terminal-debug|
+ Starting |termdebug-starting|
+ Example session |termdebug-example|
+ Stepping through code |termdebug-stepping|
+ Inspecting variables |termdebug-variables|
+ Other commands |termdebug-commands|
+ Prompt mode |termdebug-prompt|
+ Communication |termdebug-communication|
+ Customizing |termdebug-customizing|
+
+{Vi does not have any of these commands}
+{only available when compiled with the |+terminal| feature}
+The terminal feature requires the |+multi_byte|, |+job| and |+channel| features.
+
+==============================================================================
+1. Basic use *terminal-use*
+
+This feature is for running a terminal emulator in a Vim window. A job can be
+started connected to the terminal emulator. For example, to run a shell: >
+ :term bash
+
+Or to run build command: >
+ :term make myprogram
+
+The job runs asynchronously from Vim, the window will be updated to show
+output from the job, also while editing in another window.
+
+
+Typing ~
+ *terminal-typing*
+When the keyboard focus is in the terminal window, typed keys will be sent to
+the job. This uses a pty when possible. You can click outside of the
+terminal window to move keyboard focus elsewhere.
+
+CTRL-W can be used to navigate between windows and other CTRL-W commands, e.g.:
+ CTRL-W CTRL-W move focus to the next window
+ CTRL-W : enter an Ex command
+See |CTRL-W| for more commands.
+
+Special in the terminal window: *CTRL-W_.* *CTRL-W_N*
+ CTRL-W . send a CTRL-W to the job in the terminal
+ CTRL-W CTRL-\ send a CTRL-\ to the job in the terminal
+ CTRL-W N go to Terminal-Normal mode, see |Terminal-mode|
+ CTRL-\ CTRL-N go to Terminal-Normal mode, see |Terminal-mode|
+ CTRL-W " {reg} paste register {reg} *CTRL-W_quote*
+ Also works with the = register to insert the result of
+ evaluating an expression.
+ CTRL-W CTRL-C ends the job, see below |t_CTRL-W_CTRL-C|
+
+See option 'termwinkey' for specifying another key instead of CTRL-W that
+will work like CTRL-W. However, typing 'termwinkey' twice sends 'termwinkey'
+to the job. For example:
+ 'termwinkey' CTRL-W move focus to the next window
+ 'termwinkey' : enter an Ex command
+ 'termwinkey' 'termwinkey' send 'termwinkey' to the job in the terminal
+ 'termwinkey' . send 'termwinkey' to the job in the terminal
+ 'termwinkey' CTRL-\ send a CTRL-\ to the job in the terminal
+ 'termwinkey' N go to terminal Normal mode, see below
+ 'termwinkey' CTRL-N same as CTRL-W N
+ 'termwinkey' CTRL-C same as |t_CTRL-W_CTRL-C|
+ *t_CTRL-\_CTRL-N*
+The special key combination CTRL-\ CTRL-N can be used to switch to Normal
+mode, just like this works in any other mode.
+ *t_CTRL-W_CTRL-C*
+CTRL-W CTRL-C can be typed to forcefully end the job. On MS-Windows a
+CTRL-BREAK will also kill the job.
+
+If you type CTRL-C the effect depends on what the pty has been configured to
+do. For simple commands this causes a SIGINT to be sent to the job, which
+would end it. Other commands may ignore the SIGINT or handle the CTRL-C
+themselves (like Vim does).
+
+To change the keys you type use terminal mode mappings, see |:tmap|.
+These are defined like any mapping, but apply only when typing keys that are
+sent to the job running in the terminal. For example, to make F1 switch
+to Terminal-Normal mode: >
+ tnoremap <F1> <C-W>N
+You can use Esc, but you need to make sure it won't cause other keys to
+break (cursor keys start with an Esc, so they may break): >
+ tnoremap <Esc> <C-W>N
+ set notimeout ttimeout timeoutlen=100
+
+You can also create menus similar to terminal mode mappings, but you have to
+use |:tlmenu| instead of |:tmenu|.
+
+< *options-in-terminal*
+After opening the terminal window and setting 'buftype' to "terminal" the
+TerminalOpen autocommand event is triggered. This makes it possible to set
+options specifically for the window and buffer. Example: >
+ au TerminalOpen * if &buftype == 'terminal' | setlocal bufhidden=hide | endif
+The <abuf> is set to the terminal buffer, but if there is no window (hidden
+terminal) then setting options will happen in the wrong buffer, therefore the
+check for &buftype in the example.
+
+Mouse events (click and drag) are passed to the terminal. Mouse move events
+are only passed when Vim itself is receiving them. For a terminal that is
+when 'balloonevalterm' is enabled.
+
+
+Size and color ~
+ *terminal-size-color*
+See option 'termwinsize' for controlling the size of the terminal window.
+(TODO: scrolling when the terminal is larger than the window)
+
+The job running in the terminal can change the colors. The default foreground
+and background colors are taken from Vim, the Normal highlight group.
+
+For a color terminal the 'background' option is used to decide whether the
+terminal window will start with a white or black background.
+
+To use a different color the Terminal highlight group can be used, for
+example: >
+ hi Terminal ctermbg=lightgrey ctermfg=blue guibg=lightgrey guifg=blue
+<
+ *g:terminal_ansi_colors*
+In GUI mode or with 'termguicolors', the 16 ANSI colors used by default in new
+terminal windows may be configured using the variable
+`g:terminal_ansi_colors`, which should be a list of 16 color names or
+hexadecimal color codes, similar to those accepted by |highlight-guifg|. When
+not using GUI colors, the terminal window always uses the 16 ANSI colors of
+the underlying terminal.
+The |term_setansicolors()| function can be used to change the colors, and
+|term_getansicolors()| to get the currently used colors.
+
+
+Syntax ~
+
+:[range]ter[minal] [options] [command] *:ter* *:terminal*
+ Open a new terminal window.
+
+ If [command] is provided run it as a job and connect
+ the input and output to the terminal.
+ If [command] is not given the 'shell' option is used.
+ if [command] is NONE no job is started, the pty of the
+ terminal can be used by a command like gdb.
+
+ If [command] is missing the default behavior is to
+ close the terminal when the shell exits. This can be
+ changed with the ++noclose argument.
+ If [command] is present the default behavior is to
+ keep the terminal open in Terminal-Normal mode. This
+ can be changed with the ++close argument.
+
+ A new buffer will be created, using [command] or
+ 'shell' as the name, prefixed with a "!". If a buffer
+ by this name already exists a number is added in
+ parentheses. E.g. if "gdb" exists the second terminal
+ buffer will use "!gdb (1)".
+
+ If [range] is given the specified lines are used as
+ input for the job. It will not be possible to type
+ keys in the terminal window. For MS-Windows see the
+ ++eof argument below.
+
+ *term++close* *term++open*
+ Supported [options] are:
+ ++close The terminal window will close
+ automatically when the job terminates.
+ ++noclose The terminal window will NOT close
+ automatically when the job terminates.
+ ++open When the job terminates and no window
+ shows it, a window will be opened.
+ Note that this can be interruptive.
+ The last of ++close, ++noclose and ++open
+ matters and rules out earlier arguments.
+
+ ++curwin Open the terminal in the current
+ window, do not split the current
+ window. Fails if the current buffer
+ cannot be |abandon|ed.
+ ++hidden Open the terminal in a hidden buffer,
+ no window will be used.
+ ++norestore Do not include this terminal window
+ in a session file.
+ ++kill={how} When trying to close the terminal
+ window kill the job with {how}. See
+ |term_setkill()| for the values.
+ ++rows={height} Use {height} for the terminal window
+ height. If the terminal uses the full
+ Vim height (no window above or below
+ the terminal window) the command line
+ height will be reduced as needed.
+ ++cols={width} Use {width} for the terminal window
+ width. If the terminal uses the full
+ Vim width (no window left or right of
+ the terminal window) this value is
+ ignored.
+ ++eof={text} when using [range]: text to send after
+ the last line was written. Cannot
+ contain white space. A CR is
+ appended. For MS-Windows the default
+ is to send CTRL-D.
+ E.g. for a shell use "++eof=exit" and
+ for Python "++eof=exit()". Special
+ codes can be used like with `:map`,
+ e.g. "<C-Z>" for CTRL-Z.
+ ++winpty Use winpty as the virtual console.
+ ++conpty Use |ConPTY| as the virtual console.
+ If you want to use more options use the |term_start()|
+ function.
+ If you want to split the window vertically, use: >
+ :vertical terminal
+< Or short: >
+ :vert ter
+
+When the buffer associated with the terminal is forcibly unloaded or wiped out
+the job is killed, similar to calling `job_stop(job, "kill")` .
+Closing the window normally results in |E947|. When a kill method was set
+with "++kill={how}" or |term_setkill()| then closing the window will use that
+way to kill or interrupt the job. For example: >
+ :term ++kill=term tail -f /tmp/log
+
+So long as the job is running the window behaves like it contains a modified
+buffer. Trying to close the window with `CTRL-W :quit` fails. When using
+`CTRL-W :quit!` the job is ended. The text in the window is lost. The buffer
+still exists, but getting it in a window with `:buffer` will show an empty
+buffer.
+
+Trying to close the window with `CTRL-W :close` also fails. Using
+`CTRL-W :close!` will close the window and make the buffer hidden.
+
+You can use `CTRL-W :hide` to close the terminal window and make the buffer
+hidden, the job keeps running. The `:buffer` command can be used to turn the
+current window into a terminal window. If there are unsaved changes this
+fails, use ! to force, as usual.
+
+To have a background job run without a window, and open the window when it's
+done, use options like this: >
+ :term ++hidden ++open make
+Note that the window will open at an unexpected moment, this will interrupt
+what you are doing.
+
+ *E947* *E948*
+So long as the job is running, the buffer is considered modified and Vim
+cannot be quit easily, see |abandon|.
+
+When the job has finished and no changes were made to the buffer: closing the
+window will wipe out the buffer.
+
+Before changes can be made to a terminal buffer, the 'modifiable' option must
+be set. This is only possible when the job has finished. At the first change
+the buffer will become a normal buffer and the highlighting is removed.
+You may want to change the buffer name with |:file| to be able to write, since
+the buffer name will still be set to the command.
+
+
+Resizing ~
+ *terminal-resizing*
+The size of the terminal can be in one of three modes:
+
+1. The 'termwinsize' option is empty: The terminal size follows the window
+ size. The minimal size is 2 screen lines with 10 cells.
+
+2. The 'termwinsize' option is "rows*cols", where "rows" is the minimal number
+ of screen rows and "cols" is the minimal number of cells.
+
+3. The 'termwinsize' option is "rowsXcols" (where the x is upper or lower
+ case). The terminal size is fixed to the specified number of screen lines
+ and cells. If the window is bigger there will be unused empty space.
+
+If the window is smaller than the terminal size, only part of the terminal can
+be seen (the lower-left part).
+
+The |term_getsize()| function can be used to get the current size of the
+terminal. |term_setsize()| can be used only when in the first or second mode,
+not when 'termwinsize' is "rowsXcols".
+
+
+Terminal-Job and Terminal-Normal mode ~
+ *Terminal-mode* *Terminal-Job*
+When the job is running the contents of the terminal is under control of the
+job. That includes the cursor position. Typed keys are sent to the job.
+The terminal contents can change at any time. This is called Terminal-Job
+mode.
+
+Use CTRL-W N (or 'termwinkey' N) to switch to Terminal-Normal mode. Now the
+contents of the terminal window is under control of Vim, the job output is
+suspended. CTRL-\ CTRL-N does the same.
+
+Terminal-Job mode is where |:tmap| mappings are applied. Keys sent by
+|term_sendkeys()| are not subject to tmap, but keys from |feedkeys()| are.
+
+It is not possible to enter Insert mode from Terminal-Job mode.
+
+ *Terminal-Normal* *E946*
+In Terminal-Normal mode you can move the cursor around with the usual Vim
+commands, Visually mark text, yank text, etc. But you cannot change the
+contents of the buffer. The commands that would start insert mode, such as
+'i' and 'a', return to Terminal-Job mode. The window will be updated to show
+the contents of the terminal. |:startinsert| is ineffective.
+
+In Terminal-Normal mode the statusline and window title show "(Terminal)". If
+the job ends while in Terminal-Normal mode this changes to
+"(Terminal-finished)".
+
+When the job outputs lines in the terminal, such that the contents scrolls off
+the top, those lines are remembered and can be seen in Terminal-Normal mode.
+The number of lines is limited by the 'termwinscroll' option. When going over
+this limit, the first 10% of the scrolled lines are deleted and are lost.
+
+
+Cursor style ~
+ *terminal-cursor-style*
+By default the cursor in the terminal window uses a not blinking block. The
+normal xterm escape sequences can be used to change the blinking state and the
+shape. Once focus leaves the terminal window Vim will restore the original
+cursor.
+
+An exception is when xterm is started with the "-bc" argument, or another way
+that causes the cursor to blink. This actually means that the blinking flag
+is inverted. Since Vim cannot detect this, the terminal window cursor
+blinking will also be inverted.
+
+
+Session ~
+ *terminal-session*
+A terminal window will be restored when using a session file, if possible and
+wanted.
+
+If "terminal" was removed from 'sessionoptions' then no terminal windows will
+be restored.
+
+If the job in the terminal was finished the window will not be restored.
+
+If the terminal can be restored, the command that was used to open it will be
+used again. To change this use the |term_setrestore()| function. This can
+also be used to not restore a specific terminal by setting the command to
+"NONE".
+
+
+Special keys ~
+ *terminal-special-keys*
+Since the terminal emulator simulates an xterm, only escape sequences that
+both Vim and xterm recognize will be available in the terminal window. If you
+want to pass on other escape sequences to the job running in the terminal you
+need to set up forwarding. Example: >
+ tmap <expr> <Esc>]b SendToTerm("\<Esc>]b")
+ func SendToTerm(what)
+ call term_sendkeys('', a:what)
+ return ''
+ endfunc
+
+
+Unix ~
+ *terminal-unix*
+On Unix a pty is used to make it possible to run all kinds of commands. You
+can even run Vim in the terminal! That's used for debugging, see below.
+
+Environment variables are used to pass information to the running job:
+ TERM the name of the terminal, from the 'term' option or
+ $TERM in the GUI; falls back to "xterm" if it does not
+ start with "xterm"
+ ROWS number of rows in the terminal initially
+ LINES same as ROWS
+ COLUMNS number of columns in the terminal initially
+ COLORS number of colors, 't_Co' (256*256*256 in the GUI)
+ VIM_SERVERNAME v:servername
+ VIM_TERMINAL v:version
+
+
+MS-Windows ~
+ *terminal-ms-windows*
+On MS-Windows winpty is used to make it possible to run all kind of commands.
+Obviously, they must be commands that run in a terminal, not open their own
+window.
+
+You need the following two files from winpty:
+
+ winpty.dll
+ winpty-agent.exe
+
+You can download them from the following page:
+
+ https://github.com/rprichard/winpty
+
+Just put the files somewhere in your PATH. You can set the 'winptydll' option
+to point to the right file, if needed. If you have both the 32-bit and 64-bit
+version, rename to winpty32.dll and winpty64.dll to match the way Vim was
+build.
+ *ConPTY*
+On more recent versions of MS-Windows 10 (beginning with the "October 2018
+Update"), winpty is no longer required. On those versions, |:terminal| will use
+Windows' built-in support for hosting terminal applications, "ConPTY". When
+ConPTY is in use, there may be rendering artifacts regarding ambiguous-width
+characters. If you encounter any such issues, set 'termmode' to winpty (which
+you then must have instlled).
+
+Environment variables are used to pass information to the running job:
+ VIM_SERVERNAME v:servername
+
+==============================================================================
+2. Terminal communication *terminal-communication*
+
+There are several ways to communicate with the job running in a terminal:
+- Use |term_sendkeys()| to send text and escape sequences from Vim to the job.
+- Use the JSON API to send encoded commands from the job to Vim.
+- Use the |client-server| mechanism. This works on machines with an X server
+ and on MS-Windows.
+
+
+Vim to job: term_sendkeys() ~
+ *terminal-to-job*
+This allows for remote controlling the job running in the terminal. It is a
+one-way mechanism. The job can update the display to signal back to Vim.
+For example, if a shell is running in a terminal, you can do: >
+ call term_sendkeys(buf, "ls *.java\<CR>")
+
+This requires for the job to be in the right state where it will do the right
+thing when receiving the keys. For the above example, the shell must be
+waiting for a command to be typed.
+
+For a job that was written for the purpose, you can use the JSON API escape
+sequence in the other direction. E.g.: >
+ call term_sendkeys(buf, "\<Esc>]51;["response"]\x07")
+
+
+Job to Vim: JSON API ~
+ *terminal-api*
+The job can send JSON to Vim, using a special escape sequence. The JSON
+encodes a command that Vim understands. Example of such a message: >
+ <Esc>]51;["drop", "README.md"]<07>
+
+The body is always a list, making it easy to find the end: ]<07>.
+The <Esc>]51;msg<07> sequence is reserved by xterm for "Emacs shell", which is
+similar to what we are doing here.
+
+Currently supported commands:
+
+ call {funcname} {argument}
+
+ Call a user defined function with {argument}.
+ The function is called with two arguments: the buffer number
+ of the terminal and {argument}, the decoded JSON argument.
+ The function name must start with "Tapi_" to avoid
+ accidentally calling a function not meant to be used for the
+ terminal API.
+ The user function should sanity check the argument.
+ The function can use |term_sendkeys()| to send back a reply.
+ Example in JSON: >
+ ["call", "Tapi_Impression", ["play", 14]]
+< Calls a function defined like this: >
+ function Tapi_Impression(bufnum, arglist)
+ if len(a:arglist) == 2
+ echomsg "impression " . a:arglist[0]
+ echomsg "count " . a:arglist[1]
+ endif
+ endfunc
+< Output from `:echo` may be erased by a redraw, use `:echomsg`
+ to be able to see it with `:messages`.
+
+ drop {filename} [options]
+
+ Let Vim open a file, like the `:drop` command. If {filename}
+ is already open in a window, switch to that window. Otherwise
+ open a new window to edit {filename}.
+ Note that both the job and Vim may change the current
+ directory, thus it's best to use the full path.
+
+ [options] is only used when opening a new window. If present,
+ it must be a Dict. Similarly to |++opt|, These entries are recognized:
+ "ff" file format: "dos", "mac" or "unix"
+ "fileformat" idem
+ "enc" overrides 'fileencoding'
+ "encoding" idem
+ "bin" sets 'binary'
+ "binary" idem
+ "nobin" resets 'binary'
+ "nobinary" idem
+ "bad" specifies behavior for bad characters, see
+ |++bad|
+
+ Example in JSON: >
+ ["drop", "path/file.txt", {"ff": "dos"}]
+
+A trick to have Vim send this escape sequence: >
+ exe "set t_ts=\<Esc>]51; t_fs=\x07"
+ let &titlestring = '["call","Tapi_TryThis",["hello",123]]'
+ redraw
+ set t_ts& t_fs&
+
+Rationale: Why not allow for any command or expression? Because that might
+create a security problem.
+
+
+Using the client-server feature ~
+ *terminal-client-server*
+This only works when v:servername is not empty. If needed you can set it,
+before opening the terminal, with: >
+ call remote_startserver('vim-server')
+
+$VIM_SERVERNAME is set in the terminal to pass on the server name.
+
+In the job you can then do something like: >
+ vim --servername $VIM_SERVERNAME --remote +123 some_file.c
+This will open the file "some_file.c" and put the cursor on line 123.
+
+==============================================================================
+3. Remote testing *terminal-testing*
+
+Most Vim tests execute a script inside Vim. For some tests this does not
+work, running the test interferes with the code being tested. To avoid this
+Vim is executed in a terminal window. The test sends keystrokes to it and
+inspects the resulting screen state.
+
+Functions ~
+
+|term_sendkeys()| send keystrokes to a terminal (not subject to tmap)
+|term_wait()| wait for screen to be updated
+|term_scrape()| inspect terminal screen
+
+
+==============================================================================
+4. Diffing screen dumps *terminal-diff*
+
+In some cases it can be bothersome to test that Vim displays the right
+characters on the screen. E.g. with syntax highlighting. To make this
+simpler it is possible to take a screen dump of a terminal and compare it to
+an expected screen dump.
+
+Vim uses the window size, text, color and other attributes as displayed. The
+Vim screen size, font and other properties do not matter. Therefore this
+mechanism is portable across systems. A conventional screenshot would reflect
+all differences, including font size and family.
+
+
+Writing a screen dump test for Vim ~
+ *terminal-dumptest*
+For an example see the Test_syntax_c() function in
+src/testdir/test_syntax.vim. The main parts are:
+- Write a file you want to test with. This is useful for testing syntax
+ highlighting. You can also start Vim with en empty buffer.
+- Run Vim in a terminal with a specific size. The default is 20 lines of 75
+ characters. This makes sure the dump is always this size. The function
+ RunVimInTerminal() takes care of this. Pass it the arguments for the Vim
+ command.
+- Send any commands to Vim using |term_sendkeys()|. For example: >
+ call term_sendkeys(buf, ":echo &lines &columns\<CR>")
+- Check that the screen is now in the expected state, using
+ VerifyScreenDump(). This expects the reference screen dump to be in the
+ src/testdir/dumps/ directory. Pass the name without ".dump". It is
+ recommended to use the name of the test function and a sequence number, so
+ that we know what test is using the file.
+- Repeat sending commands and checking the state.
+- Finally stop Vim by calling StopVimInTerminal().
+
+The first time you do this you won't have a screen dump yet. Create an empty
+file for now, e.g.: >
+ touch src/testdir/dumps/Test_function_name_01.dump
+
+The test will then fail, giving you the command to compare the reference dump
+and the failed dump, e.g.: >
+ call term_dumpdiff("Test_func.dump.failed", "dumps/Test_func.dump")
+
+Use this command in Vim, with the current directory set to src/testdir.
+Once you are satisfied with the test, move the failed dump in place of the
+reference: >
+ :!mv Test_func.dump.failed dumps/Test_func.dump
+
+
+Creating a screen dump ~
+ *terminal-screendump*
+
+To create the screen dump, run Vim (or any other program) in a terminal and
+make it show the desired state. Then use the |term_dumpwrite()| function to
+create a screen dump file. For example: >
+ :call term_dumpwrite(77, "mysyntax.dump")
+
+Here "77" is the buffer number of the terminal. Use `:ls!` to see it.
+
+You can view the screen dump with |term_dumpload()|: >
+ :call term_dumpload("mysyntax.dump")
+
+To verify that Vim still shows exactly the same screen, run Vim again with
+exactly the same way to show the desired state. Then create a screen dump
+again, using a different file name: >
+ :call term_dumpwrite(88, "test.dump")
+
+To assert that the files are exactly the same use |assert_equalfile()|: >
+ call assert_equalfile("mysyntax.dump", "test.dump")
+
+If there are differences then v:errors will contain the error message.
+
+
+Comparing screen dumps ~
+ *terminal-diffscreendump*
+
+|assert_equalfile()| does not make it easy to see what is different.
+To spot the problem use |term_dumpdiff()|: >
+ call term_dumpdiff("mysyntax.dump", "test.dump")
+
+This will open a window consisting of three parts:
+1. The contents of the first dump
+2. The difference between the first and second dump
+3. The contents of the second dump
+
+You can usually see what differs in the second part. Use the 'ruler' to
+relate it to the position in the first or second dump. Letters indicate the
+kind of difference:
+ X different character
+ > cursor in first but not in second
+ < cursor in second but not in first
+ w character width differs (single vs double width)
+ f foreground color differs
+ b background color differs
+ a attribute differs (bold, underline, reverse, etc.)
+ ? character missing in both
+ + character missing in first
+ - character missing in second
+
+Alternatively, press "s" to swap the first and second dump. Do this several
+times so that you can spot the difference in the context of the text.
+
+==============================================================================
+5. Debugging *terminal-debug* *terminal-debugger*
+
+The Terminal debugging plugin can be used to debug a program with gdb and view
+the source code in a Vim window. Since this is completely contained inside
+Vim this also works remotely over an ssh connection.
+
+When the |+terminal| feature is missing, the plugin will use the "prompt"
+buffer type, if possible. The running program will then use a newly opened
+terminal window. See |termdebug-prompt| below for details.
+
+
+Starting ~
+ *termdebug-starting*
+Load the plugin with this command: >
+ packadd termdebug
+< *:Termdebug*
+To start debugging use `:Termdebug` or `:TermdebugCommand` followed by the
+command name, for example: >
+ :Termdebug vim
+
+This opens two windows:
+
+gdb window A terminal window in which "gdb vim" is executed. Here you
+ can directly interact with gdb. The buffer name is "!gdb".
+
+program window A terminal window for the executed program. When "run" is
+ used in gdb the program I/O will happen in this window, so
+ that it does not interfere with controlling gdb. The buffer
+ name is "gdb program".
+
+The current window is used to show the source code. When gdb pauses the
+source file location will be displayed, if possible. A sign is used to
+highlight the current position, using highlight group debugPC.
+
+If the buffer in the current window is modified, another window will be opened
+to display the current gdb position. You can use `:Winbar` to add a window
+toolbar there.
+
+Focus the terminal of the executed program to interact with it. This works
+the same as any command running in a terminal window.
+
+When the debugger ends, typically by typing "quit" in the gdb window, the two
+opened windows are closed.
+
+Only one debugger can be active at a time.
+ *:TermdebugCommand*
+If you want to give specific commands to the command being debugged, you can
+use the `:TermdebugCommand` command followed by the command name and
+additional parameters. >
+ :TermdebugCommand vim --clean -c ':set nu'
+
+Both the `:Termdebug` and `:TermdebugCommand` support an optional "!" bang
+argument to start the command right away, without pausing at the gdb window
+(and cursor will be in the debugged window). For example: >
+ :TermdebugCommand! vim --clean
+
+To attach gdb to an already running executable or use a core file, pass extra
+arguments. E.g.: >
+ :Termdebug vim core
+ :Termdebug vim 98343
+
+If no argument is given, you'll end up in a gdb window, in which you need to
+specify which command to run using e.g. the gdb `file` command.
+
+
+Example session ~
+ *termdebug-example*
+Start in the Vim "src" directory and build Vim: >
+ % make
+Start Vim: >
+ % ./vim
+Load the termdebug plugin and start debugging Vim: >
+ :packadd termdebug
+ :Termdebug vim
+You should now have three windows:
+ source - where you started, has a window toolbar with buttons
+ gdb - you can type gdb commands here
+ program - the executed program will use this window
+
+You can use CTRL-W CTRL-W or the mouse to move focus between windows.
+Put focus on the gdb window and type: >
+ break ex_help
+ run
+Vim will start running in the program window. Put focus there and type: >
+ :help gui
+Gdb will run into the ex_help breakpoint. The source window now shows the
+ex_cmds.c file. A red "1 " marker will appear in the signcolumn where the
+breakpoint was set. The line where the debugger stopped is highlighted. You
+can now step through the program. Let's use the mouse: click on the "Next"
+button in the window toolbar. You will see the highlighting move as the
+debugger executes a line of source code.
+
+Click "Next" a few times until the for loop is highlighted. Put the cursor on
+the end of "eap->arg", then click "Eval" in the toolbar. You will see this
+displayed:
+ "eap->arg": 0x555555e68855 "gui" ~
+This way you can inspect the value of local variables. You can also focus the
+gdb window and use a "print" command, e.g.: >
+ print *eap
+If mouse pointer movements are working, Vim will also show a balloon when the
+mouse rests on text that can be evaluated by gdb.
+
+Now go back to the source window and put the cursor on the first line after
+the for loop, then type: >
+ :Break
+You will see a ">>" marker appear, this indicates the new breakpoint. Now
+click "Cont" in the toolbar and the code until the breakpoint will be
+executed.
+
+You can type more advanced commands in the gdb window. For example, type: >
+ watch curbuf
+Now click "Cont" in the toolbar (or type "cont" in the gdb window). Execution
+will now continue until the value of "curbuf" changes, which is in do_ecmd().
+To remove this watchpoint again type in the gdb window: >
+ delete 3
+
+You can see the stack by typing in the gdb window: >
+ where
+Move through the stack frames, e.g. with: >
+ frame 3
+The source window will show the code, at the point where the call was made to
+a deeper level.
+
+
+Stepping through code ~
+ *termdebug-stepping*
+Put focus on the gdb window to type commands there. Some common ones are:
+- CTRL-C interrupt the program
+- next execute the current line and stop at the next line
+- step execute the current line and stop at the next statement,
+ entering functions
+- finish execute until leaving the current function
+- where show the stack
+- frame N go to the Nth stack frame
+- continue continue execution
+
+ *:Run* *:Arguments*
+In the window showing the source code these commands can be used to control
+gdb:
+ `:Run` [args] run the program with [args] or the previous arguments
+ `:Arguments` {args} set arguments for the next `:Run`
+
+ *:Break* set a breakpoint at the current line; a sign will be displayed
+ *:Clear* delete the breakpoint at the current line
+
+ *:Step* execute the gdb "step" command
+ *:Over* execute the gdb "next" command (`:Next` is a Vim command)
+ *:Finish* execute the gdb "finish" command
+ *:Continue* execute the gdb "continue" command
+ *:Stop* interrupt the program
+
+If 'mouse' is set the plugin adds a window toolbar with these entries:
+ Step `:Step`
+ Next `:Over`
+ Finish `:Finish`
+ Cont `:Continue`
+ Stop `:Stop`
+ Eval `:Evaluate`
+This way you can use the mouse to perform the most common commands. You need
+to have the 'mouse' option set to enable mouse clicks.
+ *:Winbar*
+You can add the window toolbar in other windows you open with: >
+ :Winbar
+
+If gdb stops at a source line and there is no window currently showing the
+source code, a new window will be created for the source code. This also
+happens if the buffer in the source code window has been modified and can't be
+abandoned.
+
+Gdb gives each breakpoint a number. In Vim the number shows up in the sign
+column, with a red background. You can use these gdb commands:
+- info break list breakpoints
+- delete N delete breakpoint N
+You can also use the `:Clear` command if the cursor is in the line with the
+breakpoint, or use the "Clear breakpoint" right-click menu entry.
+
+
+Inspecting variables ~
+ *termdebug-variables* *:Evaluate*
+ `:Evaluate` evaluate the expression under the cursor
+ `K` same
+ `:Evaluate` {expr} evaluate {expr}
+ `:'<,'>Evaluate` evaluate the Visually selected text
+
+This is similar to using "print" in the gdb window.
+You can usually shorten `:Evaluate` to `:Ev`.
+
+
+Other commands ~
+ *termdebug-commands*
+ *:Gdb* jump to the gdb window
+ *:Program* jump to the window with the running program
+ *:Source* jump to the window with the source code, create it if there
+ isn't one
+
+
+Prompt mode ~
+ *termdebug-prompt*
+When the |+terminal| feature is not supported and on MS-Windows, gdb will run
+in a buffer with 'buftype' set to "prompt". This works slightly differently:
+- The gdb window will be in Insert mode while typing commands. Go to Normal
+ mode with <Esc>, then you can move around in the buffer, copy/paste, etc.
+ Go back to editing the gdb command with any command that starts Insert mode,
+ such as `a` or `i`.
+- The program being debugged will run in a separate window. On MS-Windows
+ this is a new console window. On Unix, if the |+terminal| feature is
+ available a Terminal window will be opened to run the debugged program in.
+
+ *termdebug_use_prompt*
+Prompt mode can be used even when the |+terminal| feature is present with: >
+ let g:termdebug_use_prompt = 1
+
+
+Communication ~
+ *termdebug-communication*
+There is another, hidden, buffer, which is used for Vim to communicate with
+gdb. The buffer name is "gdb communication". Do not delete this buffer, it
+will break the debugger.
+
+Gdb has some weird behavior, the plugin does its best to work around that.
+For example, after typing "continue" in the gdb window a CTRL-C can be used to
+interrupt the running program. But after using the MI command
+"-exec-continue" pressing CTRL-C does not interrupt. Therefore you will see
+"continue" being used for the `:Continue` command, instead of using the
+communication channel.
+
+
+Customizing ~
+
+GDB command *termdebug-customizing*
+
+To change the name of the gdb command, set the "termdebugger" variable before
+invoking `:Termdebug`: >
+ let termdebugger = "mygdb"
+< *gdb-version*
+Only debuggers fully compatible with gdb will work. Vim uses the GDB/MI
+interface. The "new-ui" command requires gdb version 7.12 or later. if you
+get this error:
+ Undefined command: "new-ui". Try "help".~
+Then your gdb is too old.
+
+
+Colors *hl-debugPC* *hl-debugBreakpoint*
+
+The color of the signs can be adjusted with these highlight groups:
+- debugPC the current position
+- debugBreakpoint a breakpoint
+
+The defaults are, when 'background' is "light":
+ hi debugPC term=reverse ctermbg=lightblue guibg=lightblue
+ hi debugBreakpoint term=reverse ctermbg=red guibg=red
+
+When 'background' is "dark":
+ hi debugPC term=reverse ctermbg=darkblue guibg=darkblue
+ hi debugBreakpoint term=reverse ctermbg=red guibg=red
+
+
+Shorcuts *termdebug_shortcuts*
+
+You can define your own shortcuts (mappings) to control gdb, that can work in
+any window, using the TermDebugSendCommand() function. Example: >
+ map ,w :call TermDebugSendCommand('where')<CR>
+The argument is the gdb command.
+
+
+Popup menu *termdebug_popup*
+
+By default the Termdebug plugin sets 'mousemodel' to "popup_setpos" and adds
+these entries to the popup menu:
+ Set breakpoint `:Break`
+ Clear breakpoint `:Clear`
+ Evaluate `:Evaluate`
+If you don't want this then disable it with: >
+ let g:termdebug_popup = 0
+
+
+Vim window width *termdebug_wide*
+
+To change the width of the Vim window when debugging starts, and use a
+vertical split: >
+ let g:termdebug_wide = 163
+This will set &columns to 163 when `:Termdebug` is used. The value is restored
+when quitting the debugger.
+If g:termdebug_wide is set and &columns is already larger than
+g:termdebug_wide then a vertical split will be used without changing &columns.
+Set it to 1 to get a vertical split without every changing &columns (useful
+for when the terminal can't be resized by Vim).
+
+
+
+ vim:tw=78:ts=8:noet:ft=help:norl: