Eric Blake <ebb9 <at> byu.net> writes: > > Yes, that's definitely a portability pitfall that warrants a wrapper module. > > And in writing the testcase, I learned that cygwin 1.5 also has a bug, in > that dup2(1,1) returns 0 (but at least cygwin's dup2(1,2) returns 2). > Although you seldom see code using dup2 as a no-op for an fd onto itself, > it provides a great way to non-destructively check whether an fd is open > without having to use fcntl or _get_osfhandle (and so I did just that in > test-pipe.c).
Well, it would be nice if doing that didn't hang mingw. It looks like Microsoft has a bug, because using dup2(fd,fd) when fd is closed appears to deadlock the process. I also botched the interaction between fchdir and dup2 (they can't both define rpl_dup2). I'm working on a followup patch for both of these issues. -- Eric Blake
