diff options
Diffstat (limited to 'gcc/doc/invoke.texi')
| -rw-r--r-- | gcc/doc/invoke.texi | 24 |
1 files changed, 20 insertions, 4 deletions
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 22af6e45673..e1a3e5f291f 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -4170,10 +4170,26 @@ C++17 provides a standard way to suppress the @option{-Wimplicit-fallthrough} warning using @code{[[fallthrough]];} instead of the GNU attribute. In C++11 or C++14 users can use @code{[[gnu::fallthrough]];}, which is a GNU extension. Instead of the these attributes, it is also possible to add a "falls through" -comment to silence the warning. GCC accepts a wide range of such comments, -for example all of "Falls through.", "fallthru", "FALLS-THROUGH" work. This -comment needs to consist of two words merely, optionally followed by periods -or whitespaces. +comment to silence the warning. The whole body of the C or C++ style comment +should match one of the following regular expressions: + +@itemize @bullet + +@item @code{-fallthrough} + +@item @code{@@fallthrough@@} + +@item @code{[ \t]*FALL(S | |-)?THR(OUGH|U)\.?[ \t]*} + +@item @code{[ \t]*Fall((s | |-)[Tt]|t)hr(ough|u)\.?[ \t]*} + +@item @code{[ \t]*fall(s | |-)?thr(ough|u)\.?[ \t]*} + +@end itemize + +and the comment needs to be followed after optional whitespace and other comments +by @code{case} or @code{default} keywords or by a user label that preceeds some +@code{case} or @code{default} label. @smallexample @group |