Record formats

Use the RECFM attribute to specify the record format. The records in a file using the record model have one of the following formats:
Note: z/OS® XL C/C++ does not support Format-D files.
These formats support the following additional options for RECFM. The record formats and the options associated with them are discussed in the following sections.
A
Specifies that the file contains ASA control characters.
B
Specifies that a file is blocked. A blocked file can have more than one record in each block.
M
Specifies that the file contains machine control characters.
S
Specifies that a file is either in standard format (if it is fixed) or spanned (if it is variable). In a standard file, every block must be full before another one starts. In a spanned file, a record can be longer than a block. If it is, the record is divided into segments and stored in consecutive blocks.

Not all the I/O categories (listed in Table 1) support all of these attributes. Depending on what category you are using, z/OS XL C/C++ ignores or simulates attributes that do not apply. For more information on the record formats and the options supported for each I/O category, see Opening files.