| command | string | 
       The command string that was passed to proc_open().
       | 
| pid | int | process id | 
| running | bool | 
       TRUE if the process is still running, FALSE if it has
       terminated.
       | 
| signaled | bool | 
       TRUE if the child process has been terminated by
       an uncaught signal. Always set to FALSE on Windows.
       | 
| stopped | bool | 
       TRUE if the child process has been stopped by a
       signal. Always set to FALSE on Windows.
       | 
| exitcode | int | 
       The exit code returned by the process (which is only
       meaningful if running is FALSE).
       Only first call of this function return real value, next calls return
       -1.
       | 
| termsig | int | 
       The number of the signal that caused the child process to terminate
       its execution (only meaningful if signaled is TRUE).
       | 
| stopsig | int | 
       The number of the signal that caused the child process to stop its
       execution (only meaningful if stopped is TRUE).
       |