C K U U S R --  "User Interface" for PC-DOS Kermit

C M D L I N  --  Get arguments from command line

		 cmdlin() {

D O A R G  --	 Do a command-line argument.  */

		 doarg(x)
		 char x = character on command line to be evaluated

U S A G E  --	 Print help message , how to use

		 usage()

F A T A L  --	 Print error message and exit to dos through  doexit()

		 fatal(msg)
		 char *msg = message to print

D O E X I T  --  Close files, turn of interrupt and exit from the program

		 doexit(exitstat)
		 int exitstat = type of exit to pass to exit().

B L D L E N  --  Make length-encoded copy of string  */

		 char *bldlen(str,dest)
		 char *str = string to copy
		 char *dest = destination string

D E B O P N  --  Open a debugging file	*/

		 debopn(s)
		 char *s = name of debug file

C H K S P D  --  Check if argument is a valid baud rate  */

		 chkspd(x)
		 int x = baud rate to check

I N T M S G  --  Issue message about terminal interrupts during file
		 transfer if not quiet

		 intmsg(n)
		 long n  = if 1 print message else print ignored


C H K I N T  --  Check for console interrupts during file transfer
		 and execute them if any. Ignored if quiet = TRUE

		 chkint()

D E B U G  --	 Enter a record in the debugging log

		 debug(f,s1,s2,n)
		 Call with a format, two strings, and a number:
		 int f	  - Format, a bit string in range 0-7.
			    If bit x is on, then argument number x is printed.
		 char *s1 - String, argument number 1.	Printed as is.
		 char *s2 - String, argument number 2.	Printed in brackets.
		 int n	  - Int, argument 3.  Printed preceded by equals sign.

		 f=0 is special: print s1,s2, and interpret n as a char.

T L O G  --	 Log a record in the transaction file

		 tlog(f,s1,s2,n)
		 Call with a format and 3 arguments: two strings and a number:
		 int f	- Format, a bit string in range 0-7, bit x is on,
			  arg #x is printed.
		 char *s1,s2 - String arguments 1 and 2.
		 long  n     - Int, argument 3.

E R M S G --	 Print an error message on file stderr

		 ermsg(msg)
		 char *msg = message to print


P E R R O R --	 Print a error message and associated errno

		 perror(s)
		 char *s = message to print

S C R E E N  --  Screen display function

		 screen(f,c,n,s)
		 int f - argument descriptor (format to use)
		 int c - a character or small integer
		 long n - a long integer (used for packet number)
		 char *s - a string to print.

		 The possible values of f currently accepted are
		 defined as SCR_??? in the lckerm.h header file