linux man page for aio_read

AIO_READ(3)						     Linux Programmer's Manual						       AIO_READ(3)

NAME
       aio_read - asynchronous read

SYNOPSIS
       #include <aio.h>

       int aio_read(struct aiocb *aiocbp);

       Link with -lrt.

DESCRIPTION
       The  aio_read()	function  requests  an	asynchronous  "n  =  read(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).

       The data is read starting at the absolute file offset aiocbp->aio_offset, regardless of the current file position.  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 read 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 read from a regular file beyond its maximum offset.

RETURN VALUE
       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).

ERRORS
       EAGAIN Out of resources.

       EBADF  aio_fildes is not a valid file descriptor open for reading.

       EINVAL One or more of aio_offset, aio_reqprio, aio_nbytes are invalid.

       ENOSYS This function is not supported.

       EOVERFLOW
	      The  file  is  a regular file, we start reading before end-of-file and want at least one byte, but the starting position is past the
	      maximum offset for this file.

CONFORMING TO
       POSIX.1-2001.

NOTES
       It is a good idea to zero out the control block before use.  This control block must  not  be  changed  while  the  read  operation  is	in
       progress.   The	buffer	area  being  read into must not be accessed during the operation or undefined results may occur.  The memory areas
       involved must remain valid.

SEE ALSO
       aio_cancel(3), aio_error(3), aio_fsync(3), aio_return(3), aio_suspend(3), aio_write(3)

COLOPHON
       This page is part of release 3.27 of the Linux man-pages project.  A description of the project, and information about reporting bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

								    2003-11-14							       AIO_READ(3)