get_process_input
Void get_process_input (Int_Type tsecs);
Read all pending input by all subprocesses.  If no input is
available, this function will wait for input until tsecs tenth of
seconds have expired.
kill_process
Void kill_process (Int_Type id);
Kill the subprocess specified by the process handle id.
open_process
Int_Type open_process (name, argv1, argv2, ..., argvN, N);
Returns id of process, -1 upon failure.
process_mark
User_Mark process_mark (Int_Type id);
This function returns the user mark that contains the position of the last output by the process.
Whether or not to silently kill a process at exit
Void process_query_at_exit (Int_Type pid, Int_Type query)
The process_query_at_exit may be used to specify whether or
not the process specified by pid should be silently ignored
when the editor exits.  If the parameter query is non-zero,
the user will be reminded the process exists before exiting.
open_process, kill_process, exit_jed
run_shell_cmd
Void run_shell_cmd (String cmd);
The run_shell_cmd function may be used to run cmd in a separate
process.  Any output generated by the process is inserted into the
buffer at the current point.  It generates a S-Lang error if the
process specified by cmd could not be opened.  Otherwise, it
returns the exit status of the process.
send_process
Void send_process (Int_Type id, String s);
Undocumented
send_process_eof
send_process_eof (Int_Type pid);
This function closes the stdin of the process specified by the
handle pid.
set_process
Void set_process (Int_Type pid, String what, String value);
pid is the process handle returned by open_process.  The second
parameter, what, specifies what to set.  It must be one of the
strings:
        "signal" :  indicates that 'value' is the name of a function to call
                    when the process status changed.  The function specified
                    by 'value' must be declared to accept an argument list:
                    (pid, flags, status) where 'pid' has the same
                    meaning as above and flags is an integer with the
                    meanings: 
                      1: Process Running
                      2: Process Stopped
                      4: Process Exited Normally
                      8: Process Exited via Signal
                    The meaning of the \var{status} parameter depends
                    upon the \var{flags} parameter.  If the process
                    exited normally, then \var{status} indicates its
                    return status.  Otherwise \var{status} represents
                    the signal that either stopped or killed the
                    process.
                    Note: when this function is called, the current buffer is
                    guaranteed to be the buffer associated with the process.
       
       "output" :   This parameter determines how output from the process is
                    is processed.  If the 'value' is the empty string "", output
                    will go to the end of the buffer associated with the process
                    and the point will be left there.
                    If value is ".", output will go at the current buffer position.
                    If value is "@", output will go to the end of the buffer but
                    the point will not move.  Otherwise, 'value' is the name of
                    a slang function with arguments: (pid, data) where pid has
                    the above meaning and data is the output from the process.
signal_process
Void signal_process (Int_Type pid, Int_Type signum);
This function may be used to send a signal to the process whose
process handle is given by pid.  The pid must be a valid handle
that was returned by open_process.
open_process, kill_process, send_process_eof