HP XP20000XP24000 Disk Array - Manual (Page 160)

6-6 Performing File Access Library (FAL) Operations
Hitachi USP V Cross-OS File Exchange User’s Guide
Writing Data
reclen = datasetPut (datasetHandle, buf, buflen)
The datasetPut function writes one record from the buf into the dataset
specified by datasetHandle. Table 6-3 shows the datasetPut arguments and
return values.
Table 6-3 DatasetPut Function
Item Value Type Description
Argument datasetHandl
e
buf
buflen
DATASET_HAND
LE
char *
long
The datasetHandle value returned by the datasetOpen
function.
Buffer area for storing the write data.
Size of the buffer area. If any of the following conditions is detected,
datasetPut returns an error and does not transfer any data to the dataset:
For fixed-length record: buflen ≠ RL of the dataset
For variable-length record: (buflen + 4) > RL of dataset
For variable-length record: buflen = 0 (no data entity)
Return value reclen
-1
long Data entity size written into the dataset.
Error end
Figure 6-2 shows the format requirements for variable-length records accessed
by the datasetPut function. When the target dataset is variable-length, the
datasetPut function takes the data entity from the buf, automatically adds
the two-byte RL field, and writes the record into the dataset. When the data is
written into the dataset, multiple records are blocked within the extent defined
by the VTOC of the dataset.
Block length Record length Data entity Record length Data entity
Record length Record length
Block Length (≤block length defined in VTOC)
2 bytes 2 bytes
Block length format: Block length 0x0000
2 bytes 2 bytes
Record length format: Record length 0x0000
Figure 6-2 Format Requirements for Writing Variable-Length Records
When the datasetPut function terminates successfully, it returns the length of
the data entity written to the dataset. If the datasetPut function terminates
unsuccessfully, it returns a value of -1. To get the error code information,
execute the datasetGetLastError function (see section Acquiring Error
Information).