On Mon, Oct 5, 2026 at 1:37 PM Jonathan Wakely <[email protected]> wrote:
> This avoids pedantic warnings in C++98 caused by %zu in the format > strings passed to the __throw_out_of_range_fmt function: > > include/bitset:845: warning: ISO C++98 does not support the 'z' gnu_printf > length modifier [-Wformat=] > > The definition of the function is in src/c++11/functexcept.cc and > compiled using -std=gnu++11 so the %zu format works fine. We just can't > tell C++98 translation units that it works, so suppress the attribute in > C++98. > > libstdc++-v3/ChangeLog: > > * include/bits/stdexcept_throwfwd.h (__throw_out_of_range_fmt): > Do not use __format__ attribute for C++98. > --- > > Tested x86_64-linux. > I was going to ask if silencing the warning about the unsupported modifier wouldn't be better, but that would also disable all warnings emitted by this attribute, which gives behavior equivalent to removing it. Could you add a line about this in commit description. LGTM. > > libstdc++-v3/include/bits/stdexcept_throwfwd.h | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/libstdc++-v3/include/bits/stdexcept_throwfwd.h > b/libstdc++-v3/include/bits/stdexcept_throwfwd.h > index 9b0aad3571d3..3980a60bd5c3 100644 > --- a/libstdc++-v3/include/bits/stdexcept_throwfwd.h > +++ b/libstdc++-v3/include/bits/stdexcept_throwfwd.h > @@ -81,9 +81,13 @@ _GLIBCXX_BEGIN_NAMESPACE_VERSION > void > __throw_out_of_range(const char*) > __attribute__((__noreturn__,__cold__)); > > +#if __cplusplus >= 201103L > + // C++98 does not support %zu which is used in most calls to this > function. > + [[__gnu__::__format__(__gnu_printf__, 1, 2)]] > +#endif > void > __throw_out_of_range_fmt(const char*, ...) > - __attribute__((__noreturn__,__cold__,__format__(__gnu_printf__, 1, > 2))); > + __attribute__((__noreturn__,__cold__)); > > void > __throw_runtime_error(const char*) > __attribute__((__noreturn__,__cold__)); > -- > 2.55.0 > >
