aio_write — asynchronous write
#include <aio.h>
int
aio_write( |
struct aiocb * | aiocbp) ; |
The aio_write
() function
requests an asynchronous "n = write(fd, buf, count)" with fd,
buf, count given by aiocbp->aio_fildes
,
aiocbp->aio_buf
,
aiocbp->aio_nbytes
,
respectively. The return status n can be retrieved upon
completion using aio_return(3).
If O_APPEND
is not set, the
data is written starting at the absolute file offset
aiocbp->aio_offset
,
regardless of the current file position. If O_APPEND
is set, the data is written at the
end of the file. After this request, the value of the current
file position is unspecified.
The "asynchronous" means that this call returns as soon as the request has been enqueued; the write may or may not have completed when the call returns. One tests for completion using aio_error(3).
If _POSIX_PRIORITIZED_IO
is
defined, and this file supports it, then the asynchronous
operation is submitted at a priority equal to that of the
calling process minus aiocbp->aio_reqprio
.
The field aiocbp->aio_lio_opcode
is
ignored.
No data is written to a regular file beyond its maximum offset.
On success, 0 is returned. On error the request is not
enqueued, −1 is returned, and errno
is set appropriately. If an error is
first detected later, it will be reported via aio_return(3) (returns
status −1) and aio_error(3) (error status
whatever one would have gotten in errno
, such as EBADF).
Out of resources.
aio_fildes
is not a valid file descriptor open for writing.
The file is a regular file, we want to write at least one byte, but the starting position is at or beyond the maximum offset for this file.
One or more of aio_offset
, aio_reqprio
, aio_nbytes
are
invalid.
This function is not supported.
It is a good idea to zero out the control block before use. This control block must not be changed while the write operation is in progress. The buffer area being written out must not be accessed during the operation or undefined results may occur. The memory areas involved must remain valid.
aio_cancel(3), aio_error(3), aio_fsync(3), aio_read(3), aio_return(3), aio_suspend(3)
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