https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64064
LIU Hao <lh_mouse at 126 dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |lh_mouse at 126 dot com
--- Comment #1 from LIU Hao <lh_mouse at 126 dot com> ---
AFAICT the only issue here is that one can't pass the result of `pubseekoff()`
back to `pubseekpos()`. Both MSVCRT GCC and UCRT GCC are affected, but MSVC
isn't.
```
#include <fstream>
#include <iostream>
int main(int, char* argv[])
{
using traits = std::filebuf::traits_type;
using int_type = std::filebuf::int_type;
std::filebuf fb;
fb.open(argv[1], std::ios::in);
int_type c;
while (!traits::eq_int_type(c = fb.sbumpc(), traits::eof()))
{
std::cout << static_cast<char>(c);
auto pos = fb.pubseekoff(0, std::ios::cur, std::ios::in);
fb.pubseekpos(pos, std::ios::in);
}
std::cout << '\n';
}
```
This outputs
```
hl
ol
```
