Description, Parameters, See also – Sun Microsystems Sun StorageTek 5800 User Manual
Page 50: Write_to_data_destination, Synopsis
Description
Function pointers of read_from_data_source type are used to upload object data. The function
pointer and opaque cookie reference are supplied as arguments to
and other functions that store object data. The data source reader function will be
called repeatedly, with the supplied cookie as an argument, to gather the object data to upload
into storage.
A read_from_data_source function should read up to buf_size bytes from the data source
indicated by cookie into the buffer at location buff and return the actual number of bytes read
as the return value from the function.
There are two special return codes:
■
A return value of 0 indicates the end-of-file condition. The data should be committed to the
data store.
■
A return value of -1 indicates a request to cancel the store. The store operation should be
aborted with an error code of HCERR_ABORTED_BY_CALLBACK.
Parameters
cookie
An opaque data structure to identify this data cookie. The cookie is likely to be an open file
descriptor.
buf
Where to store the data.
buf_size
The number of available bytes of space in buf.
See Also
write_to_data_destination
Data destination template used to download object data to the cluster.
Synopsis
typedef long (*write_to_data_destination)
(void *cookie, char *buff, long buff_len);
Synchronous C Data Types
Sun StorageTek 5800 System Client API Reference Manual • June 2008
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