https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64867
David Binderman <dcb314 at hotmail dot com> changed:
What |Removed |Added
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CC| |dcb314 at hotmail dot com
--- Comment #30 from David Binderman <dcb314 at hotmail dot com> ---
(In reply to Trass3r from comment #27)
> This should really be enabled by -Wall or -Wextra as it generates code that
> may easily crash or corrupt something.
+1.
Clang errors, intel warns and for gcc you have to enable the somewhat
obscure flag -Wconditionally-supported to see anything at all.
gcc looks to be a trailer on this issue. It's not about standards conformance,
its about making it easy for users to find bugs.
Source code I used is:
struct S
{
S();
S( const S &);
~S();
char * p;
};
void f( int, ...);
void g()
{
S s1;
f( 3, s1);
};
$ /home/dcb/llvm/results/bin/clang++ sep3f.cc
sep3f.cc:19:8: error: cannot pass object of non-trivial type 'S' through
variadic function; call will abort at runtime [-Wnon-pod-varargs]
f( 3, s1);
^
1 error generated.
$ /home/dcb34/intel/oneapi/compiler/2021.3.0/linux/bin/intel64/icpc sep3f.cc
sep3f.cc(19): warning #1595: a class type that is not trivially copyable passed
through ellipsis
f( 3, s1);
^
$ /home/dcb/gcc/results/bin/g++ -c -g -O2 -Wall -Wextra sep3f.cc
$ /home/dcb/gcc/results/bin/g++ -c -g -O2 -Wall -Wextra
-Wconditionally-supported sep3f.cc
sep3f.cc: In function ‘void g()’:
sep3f.cc:19:10: warning: passing objects of non-trivially-copyable type ‘struct
S’ through ‘...’ is conditionally supported [-Wconditionally-supported]
19 | f( 3, s1);
| ~^~~~~~~~
I'll add flag -Wconditionally-supported to a build of Fedora and see
what happens.
