On Tue, 8 Aug 2023 at 10:09, Helmut Zeisel via Gcc <gcc@gcc.gnu.org> wrote: > > GCC13, c++, cygwin 64: > > auto x = 9223372036854775808L > > gives the warning: "integer constant is so large that it is unsigned" > > But actually the type is signed __int128: > > std::cout << x; > > gives the error: "ambiguous overload for ‘operator<<’ (operand types are > ‘std::ostream’ {aka ‘std::basic_ostream<char>’} and ‘__int128’" > > and > > std::cout << (x-x-1<0) << std::endl; > > prints 1. > > So what is the correct type of 9223372036854775808L ? > unsigned long, as the warning says, or signed __int128?
See https://gcc.gnu.org/bugzilla/show_bug.cgi?id=84764 and https://gcc.gnu.org/bugzilla/show_bug.cgi?id=96788