set arg "scale=30000;4*a(1)"
exec echo $arg | bc -l > bc.out &
after 3000
set pid_bc [ catch "exec pgrep bc" ]
if { $pid_bc !=1 } {
    exec killall bc
    exit
}
set fp [ open "bc.out" r ]
set out [ read $fp ]
close $fp
puts $out