EXIT CODES 
----------

1. Common utilities

	0: no error, program exited normally
	1: a command line option needing a second argument
	2: -h, --help or --version used
	3: unknown command line option given
	4: get_common: no key given on command line
	   list_commons: unused
	   scan_commons: no files to scan
	5: no database found/specified
	6: gdbm error opening database file

	The three following exit codes can only be generated by scan_commons:
	7: internal parser error; an internal counter exploded 
	8: internal parser error; jumped out of a confined switch statement
	13: internal scanner error: a diagnostic message will be shown.

2. fflow

	0: no error, program exited normally
	1: a command line option needing a second argument
	2: -h, --help or --version used
	3: unknown command line option given
	4: no files to scan
	5: unused
	6: error opening output file
	7: internal sorting error
	8: a subroutine/function recurses into itself
	9: possible recursion detected
	10: no PROGRAM entry point found for the -p option
	11: no subroutine/function entry point found for the -s option

3. ffscan

	0: no error, program exited normally and no argument mismatches are
       found.
	1: a command line option needing a second argument
	2: -h, --help or --version used
	4: no files to scan
	5: unused
	6: error opening output file
	7: internal sorting error
	8: a subroutine/function recurses into itself
    12: argument mismatches found

4. ftags
	0: no error, program exited normally
	1: unused
	2: no files given
	3: unused
	4: unused
	5: unused
	6: error opening output file

SIGNAL TRAPS
------------

Every exit code with a value larger than 20 is the value from a signal plus 20.

The signals trapped by the common utilities are (not all systems may support 
all of these):
SIGBUS, SIGSEGV, SIGALRM, SIGUSR1, SIGQUIT and SIGINT

The signals trapped by ffscan and fflow are:
SIGSEGV, SIGUSR1, SIGQUIT and SIGINT

ftags does not trap any signals.

SIGUSR1 is used by the programs to signal a memory allocation error. 
Since plain msdos does not have a SIGUSR1, SIGFPE is used instead. 

See signal(7) for the values of the signals that are generated by your system.

