https://gcc.gnu.org/bugzilla/show_bug.cgi?id=24012
Jonathan Wakely <redi at gcc dot gnu.org> changed: What |Removed |Added ---------------------------------------------------------------------------- Target Milestone|7.0 |8.0 --- Comment #19 from Jonathan Wakely <redi at gcc dot gnu.org> --- (In reply to Gerald Pfeifer from comment #4) > Historically, on some systems one had to define _POSIX_C_SOURCE to get at > fileno(), which has been used by code generated by flex() and probably > others. Yes, but you don't have to define it to 1. If you define _POSIX_C_SOURCE to 199506L or set _XOPEN_SOURCE to 500 then I think the functions we use are available, as well as fileno.