FSCB, FSCBD Macros NOREC=numrec specifies the
read operation.
number ofrecords to
Thedefault is 1.
beread in the next
1. The optionsRECFM, BUFFER, BSIZE, RECNO, and NOREC must all be
specified as self-defining terms.
2.You can use the same FSCB to reference several different files; you
can override the fileid, or any of the options, on theFSOPEN, or FSREAO macro instructions when you reference a file via
itsFSCB. However, if the FSOPEN macro instruction is used to ready an existing file, the BSIZE and fields in the FSCB are
reset to reflect actual file characteristics.
3.You can use multiple FSCBs to reference the same file, for example,
if you wanted oneFSCB for writing and a different FSCB for reading
the file. Keep in mind, however, that the file characteristics are
inherent to the file and not to the FSCB. If you establish a read
or write pointer using theRECNO option in one FSCB, that pointer
remains unchanged unless you specify theRECNO option again on the
same orany other FSCB for that file. FSCBD Use the FSCBD macro instruction to generate a DSECT for the file system
controlblock (FSCB). The format of the FSCBD macro instruction is: r ,
i [label]L- FSCBD label is an optional statement label. The first statement in the FSCBD macro expansion is labeled FSCBD. 1. You can use the labels established in the FSCB DSECT to modify the
fields in an FSCB for a particular file.An FSCB is created
explicitly by theFSCB macro instruction, and implicitly by the FSREAO, and FSOPEN macro instructions.
2. TheFSCBD macro expands as follows: FSCBD FSCBCOMM FSCBFN FSCBFr-1 FSCBITNO FSCBBUFF FSCBSIZE FSCBFV FSCBNOIT FSCBNOFD FSCBD OSECT OS CL8 DS CL8 DS CL8 DS CL2 DS H DS A OS F OS CL2 DS H DS A Command
Filename
Filetype
Filemode
Rela ti ve record (item) number
Address of read/write buffer
Length of buffer
Record format (F orV) Number of records to be read/written
Number of bytes actually read
section 6.CMS Macro Instructions 305
read operation.
number of
The
be
1. The options
specified as self-defining terms.
2.
can override the fileid, or any of the options, on the
its
reset to reflect actual file characteristics.
3.
if you wanted one
the file. Keep in mind, however, that the file characteristics are
inherent to the file and not to the FSCB. If you establish a read
or write pointer using the
remains unchanged unless you specify the
same or
control
i [label]
fields in an FSCB for a particular file.
explicitly by the
2. The
Filename
Filetype
Filemode
Rela ti ve record (item) number
Address of read/write buffer
Length of buffer
Record format (F or
Number of bytes actually read
section 6.