This command inserts a line break and indents the new line in a manner appropriate to the context. In normal code, it does the work of
newline), in a C preprocessor line it additionally inserts a ‘
\’ at the line break, and within comments it’s like
c-context-line-break isn’t bound to a key by default, but it needs a binding to be useful. The following code will bind it to
RET. We use
c-initialization-hook here to make sure the keymap is loaded before we try to change it.
(defun my-bind-clb ()
(define-key c-mode-base-map "\C-m"
(add-hook 'c-initialization-hook 'my-bind-clb)
Put mark at the end of a function definition, and put point at the beginning (
Fill a paragraph, handling C and C++ comments (
c-fill-paragraph). If any part of the current line is a comment or within a comment, this command fills the comment or the paragraph of it that point is in, preserving the comment indentation and comment delimiters.
Run the C preprocessor on the text in the region, and show the result, which includes the expansion of all the macro calls (
c-macro-expand). The buffer text before the region is also included in preprocessing, for the sake of macros defined there, but the output from this part isn’t shown.
When you are debugging C code that uses macros, sometimes it is hard to figure out precisely how the macros expand. With this command, you don’t have to figure it out; you can see the expansions.
Insert or align ‘
\’ characters at the ends of the lines of the region (
c-backslash-region). This is useful after writing or editing a C macro definition.
If a line already ends in ‘
\’, this command adjusts the amount of whitespace before it. Otherwise, it inserts a new ‘
\’. However, the last line in the region is treated specially; no ‘
\’ is inserted on that line, and any ‘
\’ there is deleted.
Highlight parts of the text according to its preprocessor conditionals. This command displays another buffer named
*CPP Edit*, which serves as a graphic menu for selecting how to display particular kinds of conditionals and their contents. After changing various settings, click on ‘
[A]pply these settings’ (or go to that buffer and type
a) to rehighlight the C mode buffer accordingly.
Display the syntactic information about the current source line (
c-show-syntactic-information). This information directs how the line is indented.
CWarn minor mode highlights certain suspicious C and C++ constructions:
- Assignments inside expressions.
- Semicolon following immediately after ‘
for’, and ‘
while’ (except after a ‘
do … while’ statement);
- C++ functions with reference parameters.
You can enable the mode for one buffer with the command
M-x cwarn-mode, or for all suitable buffers with the command
M-x global-cwarn-mode or by customizing the variable
global-cwarn-mode. You must also enable Font Lock mode to make it work.
Hide-ifdef minor mode hides selected code within ‘
#if’ and ‘
#ifdef’ preprocessor blocks. If you change the variable
t, Hide-ifdef minor mode shadows preprocessor blocks by displaying them with a less prominent face, instead of hiding them entirely. See the documentation string of
hide-ifdef-mode for more information.
Find a file related in a special way to the file visited by the current buffer. Typically this will be the header file corresponding to a C/C++ source file, or vice versa. The variable
ff-related-file-alist specifies how to compute related file names.