Paul Eggert asks: > > On HP-UX 11.31, however, the exec() call transforms a closed file > > descriptor to a file descriptor that behaves identically to /dev/null, > > regarding fstat and fcntl. > > Does this happen for all file decriptors, or only for file descriptors 0, 1, > and > 2?
Only for 0, 1, 2. > If the latter, then HP-UX mostly conforms to POSIX except for its weird > behavior on 'read', as the POSIX spec for execlp says that if one of these > file > descriptors are closed, the execed process may see them open on an > unspecified file. Oh well. Then it's even POSIX compliant. But HP-UX (and possibly Windows) is the only platform where things are really like this - otherwise we would have seen more platforms where the diffutils 'new-file' test fails. Bruno