CC Mode provides some tools to help keep the line continuation backslashes in macros neat and tidy. Their precise action is customized with these variables:
These variables control the alignment columns for line continuation backslashes in multiline macros. They are used by the functions that automatically insert or align such backslashes, e.g.,
c-backslash-columnspecifies the minimum column for the backslashes. If any line in the macro goes past this column, then the next tab stop (i.e., next multiple of
tab-width) in that line is used as the alignment column for all the backslashes, so that they remain in a single column. However, if any lines go past
c-backslash-max-columnthen the backslashes in the rest of the macro will be kept at that column, so that the lines which are too long “stick out” instead.
Don't ever set these variables to
nil. If you want to disable the automatic alignment of backslashes, use
Align automatically inserted line continuation backslashes if non-
nil. When line continuation backslashes are inserted automatically for line breaks in multiline macros, e.g., by
c-context-line-break, they are aligned with the other backslashes in the same macro if this flag is set.
nil, automatically inserted backslashes are preceded by a single space, and backslashes get aligned only when you explicitly invoke the command