lio_listio - initiate a list of I/O requests
Real-time library (librt, -lrt)
#include <aio.h>
int lio_listio(int mode,
struct aiocb *restrict const aiocb_list[restrict],
int nitems, struct sigevent *restrict sevp);The lio_listio() function initiates the list of I/O
operations described by the array aiocb_list.
The mode operation has one of the following values:
The call blocks until all operations are complete. The sevp
argument is ignored.
The I/O operations are queued for processing and the call returns
immediately. When all of the I/O operations complete, asynchronous
notification occurs, as specified by the sevp argument; see
sigevent(3type) for details. If sevp is NULL,
no asynchronous notification occurs.
The aiocb_list argument is an array of pointers to
aiocb structures that describe I/O operations. These operations
are executed in an unspecified order. The nitems argument
specifies the size of the array aiocb_list. Null pointers in
aiocb_list are ignored.
In each control block in aiocb_list, the
aio_lio_opcode field specifies the I/O operation to be
initiated, as follows:
Initiate a read operation. The operation is queued as for a call to aio_read(3) specifying this control block.
Initiate a write operation. The operation is queued as for a call to aio_write(3) specifying this control block.
Ignore this control block.
The remaining fields in each control block have the same meanings as
for aio_read(3) and aio_write(3). The
aio_sigevent fields of each control block can be used to
specify notifications for the individual I/O operations (see
sigevent(7)).
If mode is LIO_NOWAIT,
lio_listio() returns 0 if all I/O operations are
successfully queued. Otherwise, -1 is returned, and errno is
set to indicate the error.
If mode is LIO_WAIT,
lio_listio() returns 0 when all of the I/O operations
have completed successfully. Otherwise, -1 is returned, and
errno is set to indicate the error.
The return status from lio_listio() provides
information only about the call itself, not about the individual I/O
operations. One or more of the I/O operations may fail, but this does
not prevent other operations completing. The status of individual I/O
operations in aiocb_list can be determined using
aio_error(3). When an operation has completed, its
return status can be obtained using aio_return(3).
Individual I/O operations can fail for the reasons described in
aio_read(3) and aio_write(3).
The lio_listio() function may fail for the following reasons:
Out of resources.
The number of I/O operations specified by nitems would cause
the limit AIO_MAX to be exceeded.
mode was LIO_WAIT and a signal was caught
before all I/O operations completed; see signal(7).
(This may even be one of the signals used for asynchronous I/O
completion notification.)
mode is invalid, or nitems exceeds the limit
AIO_LISTIO_MAX.
One of more of the operations specified by aiocb_list
failed. The application can check the status of each operation using
aio_return(3).
If lio_listio() fails with the error
EAGAIN, EINTR, or
EIO, then some of the operations in aiocb_list
may have been initiated. If lio_listio() fails for any
other reason, then none of the I/O operations has been initiated.
For an explanation of the terms used in this section, see attributes(7).
| Interface | Attribute | Value |
| Thread safety | MT-Safe |
POSIX.1-2008.
glibc 2.1. POSIX.1-2001.
It is a good idea to zero out the control blocks before use. The control blocks must not be changed while the I/O operations are in progress. The buffer areas being read into or written from must not be accessed during the operations or undefined results may occur. The memory areas involved must remain valid.
Simultaneous I/O operations specifying the same aiocb
structure produce undefined results.
aio_cancel(3), aio_error(3), aio_fsync(3), aio_return(3), aio_suspend(3), aio_write(3), aio(7)