Accessing Files Programmer's Guide (32650-90885)

58 Chapter2
Creating A File
Specifying a Record Format
data and the filler.
Figure 2-4. depicts a file with undefined-length records. When data does not fill the space
allocated, filler occupies the unused space.
Figure 2-4. Undefined-Length Records
The three record formats, fixed-length, variable-length, and undefined-length are
summarized in Table 2-4. on page 58
Table 2-4. Comparison of Logical Record Formats
Fixed-Length Variable-Length Undefined-Length
Data length known to file
system.
Data length known to file
system.
Data length not known to file
system.
Same length for all records. Record length varies. Same length for all records.
Record space contains data
only.
Record space contains data
plus byte count.
Record space contains data
plus filler.
Request actual size for
records.
Request maximum size for
records.
Request maximum size for
records.