Jarkko Hietaniemi <[EMAIL PROTECTED]> writes:
> -Wall -ansi -pedantic -Wtraditional -Wstrict-prototypes
> -Wmissing-prototypes -Winline -Wredundant-decls -Wnested-externs
> -Wshadow -Wpointer-arith -Wcast-qual -Wcast-align -Wwrite-strings
> -Wconversion -Waggregate-return -Winline
> The only problem with that is that many system headers do not escape
> unscathed :-)
-ansi is very difficult to use in practice because it enables various
settings in gcc that cause many symbols normally visible in system header
files to disappear. One then has to start playing with the various
feature test macros (_POSIX_SOURCE, _XOPEN_SOURCE, etc.) in order to get
them to come back, with inconsistent and frustrating results on various
platforms. I'd love to be able to use -ansi for my source, but I'm not
sure it's practical.
I generally add -W, although that requires then tagging unused parameters
to functions with the appropriate __attribute__, and can cause noise if
you use setjmp/longjmp.
I add -Wbad-function-cast.
-Wconversion I find interesting, but it can be hard to live with and can
require adding casts that really aren't necessary in order to silence the
compiler (and therefore uglification of code to a degree).
It's worth noting that -Wtraditional is specifically recommended only for
use when converting a large code base from K&R to ANSI C. If you're
assuming ANSI C, the recommendation is to not use it, since it complains
about things that are perfectly valid ANSI C and the best way of writing
some constructs. I don't believe that the list in the gcc info page of
what this turns on is actually comprehensive.
--
Russ Allbery ([EMAIL PROTECTED]) <http://www.eyrie.org/~eagle/>
