Windowing Functions
These functions implement a very basic text mode windowing system. They are good for basic menuing
systems. Some of the functions just draw on the screen, and others actually work to save and restore
what is under the screen area. All co-ordinates are established from the upper left-hand corner of
the screen, not relative to the corner of their window. Again, these are 'good enough'. To use them,
you don't have to learn curses, just link in libcurses with your application.
These routines are, by default, compiled to initialize and be available automatically. If you do not
want this as the default mode of operation, you need to modify the config.h.in file that is distributed
with the package before running the configure command. You need to comment out the line near the top
of that file that reads
#undef DWINDOW
Commenting this line will disable the the define in config.h that is generated during the configure
process. The routines are still part of the library, but they are not initialized by default. If you
want to manually initialize and use them, you will need to use the call (not otherwise documented here)
init_dwin();
These functions depend upon an environment variable named HELP to be set. On the original keypad
for the NIXDORF systems the key labelled 'HELP' was used to 'escape' from system pauses and
error messages, or to return false from keyboard prompts. As a result, the word help was used for
the environment variable. If the variable is not set, the 'help key' defaults to the 'home' key.
To set the environment variable, you need to either give it a numeric value or a key sequence.
The numeric value is the decimal value of the key sequence. For example if you wanted the help
sequence to be <CTRL><D> you would set the environment variable HELP to
either the value 4, or the string "^D". Any key can be established as the help key, but it
doesn't make sense to use some values (like the backspace key).
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