spot/m4/gccwarn.m4
Alexandre Duret-Lutz f0edfdef2b activate -Wpedantic
Fixes #214.

* m4/gccwarn.m4: Add -Wpedantic.
2017-02-01 18:02:40 +01:00

57 lines
1.9 KiB
Text

dnl Check if the compiler supports useful warning options. There's a few that
dnl we don't use, simply because they're too noisy:
dnl
dnl -ansi (prevents declaration of functions like strdup, and because
dnl it makes warning in system headers).
dnl -Wconversion (useful in older versions of gcc, but not in gcc 2.7.x)
dnl -Wtraditional (combines too many unrelated messages, only a few useful)
dnl -Wredundant-decls (system headers make this too noisy)
dnl -pedantic
dnl -Wunreachable-code (broken, see GCC PR/7827)
dnl -Wredundant-decls (too many warnings in GLIBC's header with old GCC)
dnl -Wstrict-prototypes (not valid in C++, gcc-3.4 complains)
dnl
dnl A few other options have been left out because they are annoying in C++.
AC_DEFUN([CF_GXX_WARNINGS],
[if test "x$GXX" = xyes; then
AC_CACHE_CHECK([for g++ warning options], ac_cv_prog_gxx_warn_flags,
[
cat > conftest.$ac_ext <<EOF
#line __oline__ "configure"
int main(int argc, char *argv[[]]) { return argv[[argc-1]] == nullptr; }
EOF
cf_save_CXXFLAGS="$CXXFLAGS"
ac_cv_prog_gxx_warn_flags="-W -Wall"
for cf_opt in \
Werror \
Wint-to-void-pointer-cast \
Wzero-as-null-pointer-constant \
Wcast-align \
Wpointer-arith \
Wwrite-strings \
Wcast-qual \
Wdocumentation \
Wmissing-declarations \
Wnoexcept \
Woverloaded-virtual \
Wmisleading-indentation \
Wimplicit-fallthrough \
Wlogical-op \
Wduplicated-cond \
Wnull-dereference \
Wsuggest-override \
Wpedantic
do
CXXFLAGS="$cf_save_CXXFLAGS $ac_cv_prog_gxx_warn_flags -$cf_opt"
if AC_TRY_EVAL(ac_compile); then
ac_cv_prog_gxx_warn_flags="$ac_cv_prog_gxx_warn_flags -$cf_opt"
test "$cf_opt" = Wcast-qual && ac_cv_prog_gxx_warn_flags="$ac_cv_prog_gxx_warn_flags -DXTSTRINGDEFINES"
fi
done
rm -f conftest*
CXXFLAGS="$cf_save_CXXFLAGS"])
fi
AC_SUBST([WARNING_CXXFLAGS], ["${ac_cv_prog_gxx_warn_flags}"])
])