High-Level Screen Management Intrinsic Library Reference Manual (32424-90002)

4- 10
using IEEE formatting rules.
Examples
COBOL: 01 datadescrpt pic s9(8) comp.
FORTRAN: INTEGER*4 DATADESCRPT
Pascal: var
datadescrpt : integer;
Summary of Data Mapping Methods
Methods A, B, and C allow you to transfer data and subsets of data, but
do not allow data type conversion. Method A is the simplest of the six
methods: you can choose to transfer all data or no data. Methods B and
C allow you to transfer subsets of data. Method B transfers bytes
sequentially, starting at the beginning of the buffer. Method C allows
you to select specific fields of data from the buffer, not necessarily
from the beginning of the buffer or in sequence.
Methods D, E, and F all allow for data type conversion. Methods D and F
are alike except that D requires that the conversion instruction be cod-
ed
into your application. The advantage of method D is that it allows for
the run-time resolution of buffer formats and layout. Method F uses an
Application-ready Buffer to perform data type conversions. Unless your
application has special run-time requirements, it is recommended that
you
use method F. Method E requires that conversion instructions be coded
into your application. It is more powerful than either D or F because it
allows you to transfer data from more than one buffer. Table 4-1
summarizes the six methods.
Table 4-1. Data Mapping Summary
A B C D E F
FEATURE 0-1 10 20-30 40-50 60-70 1000-1100
--------------------------------------------------------------------
Receive or send X X
full data buffer
Buffer length X
specified by
application
Actual buffer X
length returned
to application
Receive or send X
no data
Receive or send X X X X X X
data by field
Application may X X X X
specifies field
length