The following test program compiles and runs successfully with clang
20.1.8-2 and libstdc++6 16.1.1+20260801-0.1.
The same program compiled and run with libstdc++6 17.0.0+20260802-0.1
exits with a segmentation fault.
#include <print>
int main(int argc, char *argv[]) {
std::println("{}", static_cast<__int128>(argc) << 100);
}
$ clang++ -std=c++23 -g test.cpp -o test
$ ./test
1267650600228229401496703205376 (with 16.1.1)
Segmentation fault (with 17.0.0)
Martin
PS The same program fails to compile with gcc (16.1.1 or 17.0.0).
$ g++ -std=c++23 -g test.cpp -o test
In file included from
/usr/lib/gcc/x86_64-pc-cygwin/17/include/c++/print:53,
from test.cpp:1:
/usr/lib/gcc/x86_64-pc-cygwin/17/include/c++/bits/print.h: In
constructor ‘std::__format::_File_sink::_File::_File(FILE*)’:
/usr/lib/gcc/x86_64-pc-cygwin/17/include/c++/bits/print.h:198:52: error:
‘::flockfile’ has not been declared; did you mean ‘_flockfile’?
198 | explicit _File(FILE* __f) : _M_file(__f) {
::flockfile(_M_file); }
| ^~~~~~~~~
| _flockfile
/usr/lib/gcc/x86_64-pc-cygwin/17/include/c++/bits/print.h: In destructor
‘std::__format::_File_sink::_File::~_File()’:
/usr/lib/gcc/x86_64-pc-cygwin/17/include/c++/bits/print.h:199:20: error:
‘::funlockfile’ has not been declared; did you mean ‘_funlockfile’?
199 | ~_File() { ::funlockfile(_M_file); }
| ^~~~~~~~~~~
| _funlockfile
/usr/lib/gcc/x86_64-pc-cygwin/17/include/c++/bits/print.h: In member
function ‘virtual void std::__format::_File_sink::_M_overflow()’:
/usr/lib/gcc/x86_64-pc-cygwin/17/include/c++/bits/print.h:211:20: error:
‘::fwrite_unlocked’ has not been declared; did you mean
‘_fwrite_unlocked_r’?
211 | auto __n = ::fwrite_unlocked(__s.data(), 1, __s.size(),
_M_file._M_file);
| ^~~~~~~~~~~~~~~
| _fwrite_unlocked_r
/usr/lib/gcc/x86_64-pc-cygwin/17/include/c++/bits/print.h: In destructor
‘std::__format::_File_sink::~_File_sink()’:
/usr/lib/gcc/x86_64-pc-cygwin/17/include/c++/bits/print.h:232:11: error:
‘::putc_unlocked’ has not been declared; did you mean
‘_putc_unlocked_r’?
232 | ::putc_unlocked('\n', _M_file._M_file);
| ^~~~~~~~~~~~~
| _putc_unlocked_r
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