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Functions of PCFP
All of the above parameters are moved to a dynamic basic mode bank where they are
operated on by PCFP. In addition to these parameters, PLUS stack space and PLUS
work space are also allocated in the dynamic bank. The maximum possible size of the
dynamic basic mode bank limits the maximum size that can be specified for the return
area and the work area. The maximum size for most PCFP functions is the difference
between the minimum relative address, defined by MIN_DATA_ADDR, and the
maximum relative address, defined by MAX_DATA_ADDR. These definitions are
contained in the copy/include element FP$DEFS. Some functions require a different
minimum relative address or a different maximum relative address. In these cases the
function descriptions in Sections 3 – 10 indicate the minimum and maximum addresses
that apply for the function.
2.2. Data Types
The following data types are used in the item descriptions throughout this manual.
These data types are described here in a language-independent manner. Any
language-specific considerations are described in Sections 11 – 13.
Character
The item contains an ASCII character string, the maximum length of which is given in the
item description. The calling program must specify character values shorter than the
maximum by one of the following means:
• Left-justified within the item, and space-filled on the right. This is the typical method
for specifying strings in languages other than C.
• Left-justified within the item, and null-terminated on the right. (Null-terminated
means that the string is followed immediately by a null character [integer code 0],
and that all characters following the null are insignificant.) This is the typical method
for specifying strings in C.
Either of these methods can be used by a calling program written in any language. It is
permissible for some strings to be specified using one method, and others to be
specified using the other method.
In character items input to PCFP, both uppercase and lowercase letters are allowed.
PCFP treats each lowercase letter as its uppercase equivalent except where noted
otherwise. In character items returned by PCFP, letters are uppercase only, except
where noted otherwise.
Integer
The item may assume integer values. In some cases, “unsigned” is also specified to
indicate that only nonnegative integer values are legal. Unless the range of integer
values that can be assumed by the item is particularly important, it is not noted in the
item description (but can be inferred from the structure layout). Integer items are
allocated with sizes large enough so that the size of the item poses no significant
restriction on the capabilities of PCFP.
Condition
The item can assume only the values TRUE and FALSE. Internally, TRUE is represented
by 1, and FALSE is represented by 0.
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