cpan> install IO::Pty::HalfDuplex::SysctlPoll IO::Pty::HalfDuplex::SysctlPoll is up to date (undef). cpan> install IO::Pty::HalfDuplex::PTrace IO::Pty::HalfDuplex::PTrace is up to date (undef). #### nathan@warthog:~$ perl -e ' use IO::Pty::HalfDuplex; my $pty = IO::Pty::HalfDuplex->new(backend => "SysctlPoll"); $pty->spawn("nethack") or warn "Spawn failed: $@$!"; print $pty->read; ' XS code for IO::Pty::HalfDuplex::SysctlPoll not built. at /usr/local/share/perl/5.10.1/IO/Pty/HalfDuplex/SysctlPoll.pm line 44. BEGIN failed--compilation aborted at /usr/local/share/perl/5.10.1/IO/Pty/HalfDuplex/SysctlPoll.pm line 46. Compilation failed in require at (eval 2) line 3. nathan@warthog:~$ perl -e ' use IO::Pty::HalfDuplex; my $pty = IO::Pty::HalfDuplex->new(backend => "PTrace"); $pty->spawn("nethack") or warn "Spawn failed: $@$!"; print $pty->read; ' XS code for IO::Pty::HalfDuplex::PTrace not built. at /usr/local/share/perl/5.10.1/IO/Pty/HalfDuplex/PTrace.pm line 45. BEGIN failed--compilation aborted at /usr/local/share/perl/5.10.1/IO/Pty/HalfDuplex/PTrace.pm line 47. Compilation failed in require at (eval 2) line 3. nathan@warthog:~$