System Interface Guide

I/O Behavior

Asynchronous I/O

There is no guarantee that asynchronous I/O operations will be done in the sequence in which they are queued to the kernel. Nor is there any guarantee that asynchronous operations will be returned to the caller in the sequence in which they were done.

If a single buffer is specified for a rapid sequence of calls to aioread(3AIO), there is no guarantee about the state of the buffer between the time that the first call is made and the time that the last result is signaled to the caller.

An individual aio_result_t structure can be used only for one asynchronous read or write at a time.

Real-time Files

SunOS 5.0 through 5.8 provides no facilities to ensure that files will be allocated as physically contiguous.

For regular files, the read(2) and write(2) operations are always buffered. An application can use mmap(2) and msync(3C) to effect direct I/O transfers between secondary storage and process memory.