AIO_WRITE(3) | Library Functions Manual | AIO_WRITE(3) |
If O_APPEND is set for aiocbp->aio_fildes, aio_write() operations append to the file in the same order as the calls were made. If O_APPEND is not set for the file descriptor, the write operation will occur at the absolute position from the beginning of the file plus aiocbp->aio_offset.
If _POSIX_PRIORITIZED_IO is defined, and the descriptor supports it, then the enqueued operation is submitted at a priority equal to that of the calling process minus aiocbp->aio_reqprio.
The aiocbp pointer may be subsequently used as an argument to aio_return() and aio_error() in order to determine return or error status for the enqueued operation while it is in progress.
If the request is successfully enqueued, the value of aiocbp->aio_offset can be modified during the request as context, so this value must not be referenced after the request is enqueued.
The asynchronous I/O control buffer aiocbp should be zeroed before the aio_write() system call to avoid passing bogus context information to the kernel.
Modifications of the Asynchronous I/O Control Block structure or the buffer contents after the request has been enqueued, but before the request has completed, are not allowed.
If the file offset in aiocbp->aio_offset is past the offset maximum for aiocbp->aio_fildes, no I/O will occur.
The following conditions may be synchronously detected when the aio_write() system call is made, or asynchronously, at any time thereafter. If they are detected at call time, aio_write() returns -1 and sets errno appropriately; otherwise the aio_return() system call must be called, and will return -1, and aio_error() must be called to determine the actual value that would have been returned in errno.
If the request is successfully enqueued, but subsequently canceled or an error occurs, the value returned by the aio_return() system call is per the write(2) system call, and the value returned by the aio_error() system call is either one of the error returns from the write(2) system call, or one of:
May 17, 2010 | NetBSD 6.1 |