hdfsPwrite()
Supported by libMapRClient for hadoop-2.x
Writes starting at a specified position in an open file.
Whereas hdfsWrite() increments the
current offset by the amount of bytes returned by the API (except
in case of error), hdfsPwrite() does not change the
value of current offset. If the current offset before the call to
hdfsPwrite() is 0 and you specify the offset 10 for
the write operation, after the write the current offset remains
0.
If a call to hdfsPwrite() specifies
an offset that is past the end of the file, the result is a hole in
the file between the previous end of the file and the offset at
which the write begins.
You can obtain the size of a file in bytes by
calling hdfsGetPathInfo().
Flushes to the server happen automatically at
intervals during a write operation. After a write operation is
finished, either call hdfsFlush() explicitly or call
hdfsFlush() implicitly by calling
hdfsCloseFile() to be sure that any data remaining in
the write buffer is flushed.
On error, pending write buffers are flushed to the server.
Signature
tSize hdfsPwrite(hdfsFS fs, hdfsFile file, tOffset position, const void* buffer, tSize length)Parameters
| Parameter | Description |
|---|---|
| fs | The handle of the file system where the file is located. Obtain this
handle with one of the hdfsConnect() APIs. |
| file | The handle of the file. Obtain this handle with
one of the hdfsOpenFile() APIs. |
| position | The offset at which to start writing. |
| buffer | The data to write. |
| length | The number of bytes to write. The maximum length
is the maximum size of tSize. |
Return Value
Returns the number of bytes written, -1 on error.
Check errno for error codes and meanings.