HP 50g Graphing Calculator - Manual (Page 763)

Page 24-3
Calculator flags
A flag is a variable that can either be set or unset. The status of a flag affects
the behavior of the calculator, if the flag is a system flag, or of a program, if it is
a user flag. They are described in more detail next.
System flags
System flags can be accessed by using H @)FLAGS! . Press the down arrow key
to see a listing of all the system flags with their number and brief description.
The first two screens with system flags are shown below:
You will recognize many of these flags because they are set or unset in the
MODES menu (e.g., flag 95 for Algebraic mode, 103 for Complex mode, etc.).
Throughout this user’s manual we have emphasized the differences between
CHOOSE boxes and SOFT menus, which are selected by setting or un-setting
system flag 117. Another example of system flag setting is that of system flags
60 and 61 that relate to the constant library (CONLIB, see Chapter 3). These
flags operate in the following manner:
Θ user flag 60: clear (default):SI units, set: ENGL units
Θ user flag 61: clear (default):use units, set: value only
Functions for setting and changing flags
These functions can be used to set, un-set, or check on the status of user flags or
system flags. When used with these functions system flags are referred to with
negative integer numbers. Thus, system flag 117 will be referred to as flag -
117. On the other hand, user flags will be referred to as positive integer
numbers when applying these functions. It is important to understand that user
flags have applications only in programming to help control the program flow.
Functions for manipulating calculator flags are available in the PRG/MODES/
FLAG menu. The PRG menu is activated with „°. The following screens
(with system flag 117 set to CHOOSE boxes) show the sequence of screens to
get to the FLAG menu: