Accessing Files Programmer's Guide (32650-90885)

112 Chapter7
Record Selection and Data Transfer
Record Selection
File must be opened with Read, Read/Write, or Update access.
Successful read returns CCE condition code and transfer length; file error results
in CCL condition code; end-of-file results in CCG condition code and returns a
transfer length of zero.
FWRITE Used for sequential write.
May be used with fixed-length, variable-length, or undefined-length record files.
File must be opened with Write, Write/SAVE, APPEND, Read/Write or Update
access.
Successful write returns CCE condition code; file error results in CCL condition
code; end-of-file results in CCG condition code.
FREADDIR Used for random-access read.
Used only with fixed or undefined-length record files.
File must be opened with Read, Read/Write, or Update access.
Successful read returns CCE condition code; file error results in CCL condition
code; end-of-file results in CCG condition code. No transfer length is returned
because you get the amount requested unless an error occurs.
FREADSEEK Used for anticipatory random-access read into file system buffers.
Used only with buffered fixed-length or undefined-length record files.
File must be opened with Read, Read/Write, or Update access.
Successful read returns CCE condition code; file error results in CCL condition
code; end-of-file results in CCG condition code.
FWRITEDIR Used for direct write.
Use only with fixed-length or undefined-length record files.
File must be opened with Write, Write/SAVE, Read/Write or Update access;
APPEND not allowed.
Successful write returns CCE condition code; file error results in CCL condition
code; end-of-file results in CCG condition code.
FUPDATE Used to update previous record (logical or physical).
Used only with fixed-length or undefined-length record files.
Table 7-1. Intrinsics for Data Transfer