Gang Wang wrote:

Yes. but funny that you invoked FD_ZERO() for sd_readers and sd_writers. You are assuming the semantics of FD_ZERO() is to "set something as zero", but on some system it is not. For example, implement fd_set as an array, then 0 is a valid value. FD_ZERO() have to initialize something as -1 ... Funny that the code treat sd_actives differently.

Thanks for pointing this out, the missing initialization has been added in CVS HEAD.