Standard C Library Functions lio_listio(3C)
NAME
lio_listio - list directed I/O
SYNOPSIS
#include
int lio_listio(int mode, struct aiocb *restrict const list[],
int nent, struct sigevent *restrict sig);DESCRIPTION
The lio_listio() function allows the calling process, LWP,
or thread, to initiate a list of I/O requests within a sin-
gle function call.The mode argument takes one of the values LIO_WAIT or
LIO_NOWAIT declared in
and determines whether the function returns when the I/O operations have been com-
pleted, or as soon as the operations have been queued. Ifthe mode argument is LIO_WAIT, the function waits until all
I/O is complete and the sig argument is ignored.
If the mode argument is LIO_NOWAIT, the function returns
immediately, and asynchronous notification occurs, accordingto the sig argument, when all the I/O operations complete. If sig is NULL, no asynchronous notification occurs. If sig is not NULL, asynchronous notification occurs as specified
in signal.h(3HEAD) when all the requests in list have com-
pleted.The I/O requests enumerated by list are submitted in an unspecified order.
The list argument is an array of pointers to aiocb struc-
tures. The array contains nent elements. The array may con-
tain null elements, which are ignored.The aio_lio_opcode field of each aiocb structure specifies
the operation to be performed. The supported operations areLIO_READ, LIO_WRITE, and LIO_NOP; these symbols are defined
in
. The LIO_NOP operation causes the list entry to be ignored. If the aio_lio_opcode element is equal to
LIO_READ, then an I/O operation is submitted as if by a call
to aio_read(3C) with the aiocbp equal to the address of the
aiocb structure. If the aio_lio_opcode element is equal to
LIO_WRITE, then an I/O operation is submitted as if by a
call to aio_write(3C) with the aiocbp equal to the address
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Standard C Library Functions lio_listio(3C)
of the aiocb structure.The aio_fildes member specifies the file descriptor on which
the operation is to be performed.The aio_buf member specifies the address of the buffer to or
from which the data is to be transferred.The aio_nbytes member specifies the number of bytes of data
to be transferred.The members of the aiocb structure further describe the I/O operation to be performed, in a manner identical to that of the corresponding aiocb structure when used by the
aio_read(3C) and aio_write(3C) functions.
The nent argument specifies how many elements are members of the list, that is, the length of the array. The behavior of this function is altered according to thedefinitions of synchronized I/O data integrity completion
and synchronized I/O file integrity completion if synchron-
ized I/O is enabled on the file associated with aio_fildes.
See fcntl.h(3HEAD) definitions of O_DSYNC and O_SYNC.
For regular files, no data transfer will occur past the offset maximum established in the open file descriptionassociated with aiocbp->aio_fildes.
RETURN VALUES
If the mode argument has the value LIO_NOWAIT, and the I/O
operations are successfully queued, lio_listio() returns 0;
otherwise, it returns -1, and sets errno to indicate the
error.If the mode argument has the value LIO_WAIT, and all the
indicated I/O has completed successfully, lio_listio()
returns 0; otherwise, it returns -1, and sets errno to
indicate the error. In either case, the return value only indicates the successor failure of the lio_listio() call itself, not the status
of the individual I/O requests. In some cases, one or more
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Standard C Library Functions lio_listio(3C)
of the I/O requests contained in the list may fail. Failure of an individual request does not prevent completion of any other individual request. To determine the outcome of each
I/O request, the application must examine the error status associated with each aiocb control block. Each error status so returned is identical to that returned as a result of an
aio_read(3C) or aio_write(3C) function.
ERRORS
The lio_listio() function will fail if:
EAGAIN The resources necessary to queue all the I/O requests were not available. The error status for
each request is recorded in the aio_error member
of the corresponding aiocb structure, and can beretrieved using aio_error(3C).
EAGAIN The number of entries indicated by nent wouldcause the system-wide limit AIO_MAX to be
exceeded. EINVAL The mode argument is an improper value, or thevalue of nent is greater than AIO_LISTIO_MAX.
EINTR A signal was delivered while waiting for all I/O
requests to complete during an LIO_WAIT operation.
Note that, since each I/O operation invoked by
lio_listio() may possibly provoke a signal when it
completes, this error return may be caused by thecompletion of one (or more) of the very I/O opera-
tions being awaited. Outstanding I/O requests are not canceled, and the application can use
aio_fsync(3C) to determine if any request was ini-
tiated; aio_return(3C) to determine if any request
has completed; or aio_error(3C) to determine if
any request was canceled.EIO One or more of the individual I/O operations
failed. The application can use aio_error(3C) to
check the error status for each aiocb structure to determine the individual request(s) that failed.In addition to the errors returned by the lio_listio() func-
tion, if the lio_listio() function succeeds or fails with
errors of EAGAIN, EINTR, or EIO, then some of the I/O speci-
fied by the list may have been initiated. If theSunOS 5.11 Last change: 5 Feb 2008 3
Standard C Library Functions lio_listio(3C)
lio_listio() function fails with an error code other than
EAGAIN, EINTR, or EIO, no operations from the list have beeninitiated. The I/O operation indicated by each list element can encounter errors specific to the individual read or write function being performed. In this event, the error status for each aiocb control block contains the associated error code. The error codes that can be set are the same as would be set by a read(2) or write(2) function, with the following additional error codes possible:
EAGAIN The requested I/O operation was not queued due to resource limitations.
ECANCELED The requested I/O was canceled before the I/O
completed due to an explicit aio_cancel(3C)
request.EFBIG The aiocbp->aio_lio_opcode is LIO_WRITE, the
file is a regular file, aiocbp->aio_nbytes is
greater than 0, and the aiocbp->aio_offset is
greater than or equal to the offset maximum in the open file description associated withaiocbp->aio_fildes.
EINPROGRESS The requested I/O is in progress.
EOVERFLOW The aiocbp->aio_lio_opcode is LIO_READ, the
file is a regular file, aiocbp->aio_nbytes is
greater than 0, and the aiocbp->aio_offset is
before the end-of-file and is greater than or
equal to the offset maximum in the open file description associated withaiocbp->aio_fildes.
USAGE
The lio_listio() function has a transitional interface for
64-bit file offsets. See lf64(5).
ATTRIBUTES
See attributes(5) for descriptions of the following attri-
butes:SunOS 5.11 Last change: 5 Feb 2008 4
Standard C Library Functions lio_listio(3C)
____________________________________________________________
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
|_____________________________|_____________________________|
| Interface Stability | Committed ||_____________________________|_____________________________|
| MT-Level | MT-Safe |
|_____________________________|_____________________________|
| Standard | See standards(5). ||_____________________________|_____________________________|
SEE ALSO
close(2), exec(2), exit(2), fork(2), lseek(2), read(2),write(2), aio_cancel(3C), aio_error(3C), aio_fsync(3C),
aio_read(3C), aio_return(3C), aio_write(3C), aio.h(3HEAD),
fcntl.h(3HEAD), siginfo.h(3HEAD), signal.h(3HEAD), attri-
butes(5), lf64(5), standards(5)SunOS 5.11 Last change: 5 Feb 2008 5