xfileinput	get input from file using XtAppAddInput: invoke with 
filename command-line argument.

xpipeinput	get input from pipe using XtAppAddInput: specify on 
command-line any program that prints characters to standard out.  For 
example: xpipeinput "cal 10 1989"

xworkproc	uses a work procedure to create a popup widget using idle 
time.

xstdin		gets input from pipe from stdin.
