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lio_listio(2) [freebsd man page]

LIO_LISTIO(2)						      BSD System Calls Manual						     LIO_LISTIO(2)

NAME
lio_listio -- list directed I/O (REALTIME) LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <aio.h> int lio_listio(int mode, struct aiocb * const list[], int nent, struct sigevent *sig); DESCRIPTION
The lio_listio() function initiates a list of I/O requests with a single function call. The list argument is an array of pointers to aiocb structures describing each operation to perform, with nent elements. NULL elements are ignored. The aio_lio_opcode field of each aiocb specifies the operation to be performed. The following operations are supported: LIO_READ Read data as if by a call to aio_read(2). LIO_NOP No operation. LIO_WRITE Write data as if by a call to aio_write(2). If the mode argument is LIO_WAIT, lio_listio() does not return until all the requested operations have been completed. If mode is LIO_NOWAIT, the requests are processed asynchronously, and the signal specified by sig is sent when all operations have completed. If sig is NULL, the calling process is not notified of I/O completion. The order in which the requests are carried out is not specified; in particular, there is no guarantee that they will be executed in the order 0, 1, ..., nent-1. RETURN VALUES
If mode is LIO_WAIT, the lio_listio() function returns 0 if the operations completed successfully, otherwise -1. If mode is LIO_NOWAIT, the lio_listio() function returns 0 if the operations are successfully queued, otherwise -1. ERRORS
The lio_listio() function will fail if: [EAGAIN] There are not enough resources to enqueue the requests. [EAGAIN] The request would cause the system-wide limit AIO_MAX to be exceeded. [EINVAL] The mode argument is neither LIO_WAIT nor LIO_NOWAIT, or nent is greater than AIO_LISTIO_MAX. [EINTR] A signal interrupted the system call before it could be completed. [EIO] One or more requests failed. In addition, the lio_listio() function may fail for any of the reasons listed for aio_read(2) and aio_write(2). If lio_listio() succeeds, or fails with an error code of EAGAIN, EINTR, or EIO, some of the requests may have been initiated. The caller should check the error status of each aiocb structure individually by calling aio_error(2). SEE ALSO
aio_error(2), aio_read(2), aio_write(2), read(2), write(2), siginfo(3), aio(4) STANDARDS
The lio_listio() function is expected to conform to IEEE Std 1003.1-2001 (``POSIX.1''). BSD
January 12, 2003 BSD

Check Out this Related Man Page

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

NAME
lio_listio - initiate a list of I/O requests SYNOPSIS
#include <aio.h> int lio_listio(int mode, struct aiocb *const aiocb_list[], int nitems, struct sigevent *sevp); Link with -lrt. DESCRIPTION
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: LIO_WAIT The call blocks until all operations are complete. The sevp argument is ignored. LIO_NOWAIT The I/O operations are queued for processing and the call returns immediately. When all of the I/O operations complete, asyn- chronous notification occurs, as specified by the sevp argument; see sigevent(7) 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: LIO_READ Initiate a read operation. The operation is queued as for a call to aio_read(3) specifying this control block. LIO_WRITE Initiate a write operation. The operation is queued as for a call to aio_write(3) specifying this control block. LIO_NOP 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)). RETURN VALUE
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). ERRORS
The lio_listio() function may fail for the following reasons: EAGAIN Out of resources. EAGAIN The number of I/O operations specified by nitems would cause the limit AIO_MAX to be exceeded. EINTR 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.) EINVAL mode is invalid, or nitems exceeds the limit AIO_LISTIO_MAX. EIO 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_lis- tio() fails for any other reason, then none of the I/O operations has been initiated. VERSIONS
The lio_listio() function is available since glibc 2.1. ATTRIBUTES
For an explanation of the terms used in this section, see attributes(7). +-------------+---------------+---------+ |Interface | Attribute | Value | +-------------+---------------+---------+ |lio_listio() | Thread safety | MT-Safe | +-------------+---------------+---------+ CONFORMING TO
POSIX.1-2001, POSIX.1-2008. NOTES
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. SEE ALSO
aio_cancel(3), aio_error(3), aio_fsync(3), aio_return(3), aio_suspend(3), aio_write(3), aio(7) COLOPHON
This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/. 2017-09-15 LIO_LISTIO(3)

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