https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64064
--- Comment #3 from Jonathan Wakely <redi at gcc dot gnu.org> --- https://learn.microsoft.com/en-us/cpp/c-runtime-library/reference/fseek-fseeki64?view=msvc-170#remarks The only way to use _fseeki64 for text mode files is with __off=0 (and any value of __way) or __way=beg and __off obtained from _ftelli64. So I think for __way=cur or __way=end we would need to calculate a file offset relative to the start of the file and then use that.
