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Some warning options are, for reasons not entirely obvious to me, not 

supported by some versions of g++ even though the corresponding version
of gcc supports them.  Other versions of g++, and clang, support them.

Check, before adding a -W option for C++, whether the compiler supports
it; that check must be done with -Werror, at least with g++, in order to
get a non-zero exit status from the compiler.

svn path=/trunk/; revision=54447
This commit is contained in:
Guy Harris 2013-12-24 18:43:42 +00:00
parent 68e7ccc5dc
commit 8713e0457b
2 changed files with 50 additions and 3 deletions
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43
acinclude.m4
View File

@ -1610,6 +1610,37 @@ AC_DEFUN([AC_WIRESHARK_CHECK_UNKNOWN_WARNING_OPTION_ERROR],
CFLAGS="$save_CFLAGS"
])
dnl
dnl Check whether, if you pass a valid-for-C-but-not-C++ option to the
dnl compiler, it fails or just prints a warning message and succeeds.
dnl Set ac_wireshark_non_cxx_warning_option_error to the appropriate flag
dnl to force an error if it would otherwise just print a warning message
dnl and succeed.
dnl
AC_DEFUN([AC_WIRESHARK_CHECK_NON_CXX_WARNING_OPTION_ERROR],
[
AC_MSG_CHECKING([whether the compiler fails when given an warning option not supported for C++])
save_CXXFLAGS="$CXXFLAGS"
CXXFLAGS="$CFLAGS -Wmissing-prototypes" # the prototypical one, no pun intended
AC_LANG_PUSH(C++)
AC_TRY_COMPILE(
[],
[return 0],
[
AC_MSG_RESULT([no, adding -Werror])
#
# We're assuming this is g++, where -Werror is the
# appropriate option to force the compiler to fail.
#
ac_wireshark_non_cxx_warning_option_error="-Werror"
],
[
AC_MSG_RESULT([yes])
])
AC_LANG_POP
CXXFLAGS="$save_CXXFLAGS"
])
#
# AC_WIRESHARK_COMPILER_FLAGS_CHECK
#
@ -1720,11 +1751,21 @@ if test "x$ac_supports_gcc_flags" = "xyes" ; then
#
# Not C-only; if this can be added to the C++ compiler flags, add them.
#
# If the option begins with "-W", add
# $ac_wireshark_unknown_warning_option_error, as per the above, and
# also add $ac_wireshark_non_cxx_warning_option_error, because at
# lease some versions of g++ whine about -Wmissing-prototypes, the
# fact that at least one of those versions refuses to warn about
# function declarations without an earlier declaration nonwithstanding;
# perhaps there's a reason not to warn about that with C++ even though
# warning about it can be a Good Idea with C, but it's not obvious to
# me).
#
AC_MSG_CHECKING(whether we can add $GCC_OPTION to CXXFLAGS)
CXXFLAGS_saved="$CXXFLAGS"
if expr "x$GCC_OPTION" : "x-W.*" >/dev/null
then
CXXFLAGS="$CXXFLAGS $ac_wireshark_unknown_warning_option_error $GCC_OPTION"
CXXFLAGS="$CXXFLAGS $ac_wireshark_unknown_warning_option_error $ac_wireshark_non_cxx_warning_option_error $GCC_OPTION"
elif expr "x$GCC_OPTION" : "x-f.*" >/dev/null
then
CXXFLAGS="$CXXFLAGS -Werror $GCC_OPTION"

10
configure.ac
View File

@ -750,11 +750,17 @@ fi
AC_SUBST(HAVE_OSX_PACKAGING)
#
# Some compilers have to be told to fail on unknown warning errors;
# Some compilers have to be told to fail when passed an unknown -W flag;
# make sure we do that.
#
AC_WIRESHARK_CHECK_UNKNOWN_WARNING_OPTION_ERROR
#
# Some C++ compilers have to be told to fail when passed a -W flag that
# they don't think should apply to C++; make sure we do that.
#
AC_WIRESHARK_CHECK_NON_CXX_WARNING_OPTION_ERROR
#
# Try to add some additional gcc checks to CFLAGS
#
@ -801,7 +807,7 @@ AC_ARG_ENABLE(extra-gcc-checks,
#
# All the registration functions block these for now.
#
AC_WIRESHARK_COMPILER_FLAGS_CHECK(-Wmissing-prototypes, C)
AC_WIRESHARK_COMPILER_FLAGS_CHECK(-Wmissing-prototypes)
AC_WIRESHARK_COMPILER_FLAGS_CHECK(-Wmissing-declarations)
#
# A bunch of "that might not work on SPARC" code blocks