.\" Copyright (C) 2010, Michael Kerrisk .\" .\" %%%LICENSE_START(GPLv2+_DOC_FULL) .\" This is free documentation; you can redistribute it and/or .\" modify it under the terms of the GNU General Public License as .\" published by the Free Software Foundation; either version 2 of .\" the License, or (at your option) any later version. .\" .\" The GNU General Public License's references to "object code" .\" and "executables" are to be interpreted as the output of any .\" document formatting or typesetting system, including .\" intermediate and printed output. .\" .\" This manual is distributed in the hope that it will be useful, .\" but WITHOUT ANY WARRANTY; without even the implied warranty of .\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the .\" GNU General Public License for more details. .\" .\" You should have received a copy of the GNU General Public .\" License along with this manual; if not, see .\" . .\" %%%LICENSE_END .\" .TH LIO_LISTIO 3 2017-09-15 "" "Linux Programmer's Manual" .SH NAME lio_listio \- initiate a list of I/O requests .SH SYNOPSIS .nf .B "#include " .PP .BI "int lio_listio(int " mode ", struct aiocb *const " aiocb_list [], .BI " int " nitems ", struct sigevent *" sevp ); .PP Link with \fI\-lrt\fP. .fi .SH DESCRIPTION The .BR lio_listio () function initiates the list of I/O operations described by the array .IR aiocb_list . .PP The .I mode operation has one of the following values: .TP 12 .B LIO_WAIT The call blocks until all operations are complete. The .I sevp argument is ignored. .TP .B LIO_NOWAIT 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 .IR sevp argument; see .BR sigevent (7) for details. If .IR sevp is NULL, no asynchronous notification occurs. .PP The .I aiocb_list argument is an array of pointers to .I aiocb structures that describe I/O operations. These operations are executed in an unspecified order. The .I nitems argument specifies the size of the array .IR aiocb_list . null pointers in .I aiocb_list are ignored. .PP In each control block in .IR aiocb_list , the .I aio_lio_opcode field specifies the I/O operation to be initiated, as follows: .TP 10 .BR LIO_READ Initiate a read operation. The operation is queued as for a call to .BR aio_read (3) specifying this control block. .TP .BR LIO_WRITE Initiate a write operation. The operation is queued as for a call to .BR aio_write (3) specifying this control block. .TP .BR LIO_NOP Ignore this control block. .PP The remaining fields in each control block have the same meanings as for .BR aio_read (3) and .BR aio_write (3). The .I aio_sigevent fields of each control block can be used to specify notifications for the individual I/O operations (see .BR sigevent (7)). .SH RETURN VALUE If .I mode is .BR LIO_NOWAIT , .BR lio_listio () returns 0 if all I/O operations are successfully queued. Otherwise, \-1 is returned, and .I errno is set to indicate the error. .PP If .I mode is .BR LIO_WAIT , .BR lio_listio () returns 0 when all of the I/O operations have completed successfully. Otherwise, \-1 is returned, and .I errno is set to indicate the error. .PP The return status from .BR 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 .IR aiocb_list can be determined using .BR aio_error (3). When an operation has completed, its return status can be obtained using .BR aio_return (3). Individual I/O operations can fail for the reasons described in .BR aio_read (3) and .BR aio_write (3). .SH ERRORS The .BR lio_listio () function may fail for the following reasons: .TP .B EAGAIN Out of resources. .TP .B EAGAIN .\" Doesn't happen in glibc(?) The number of I/O operations specified by .I nitems would cause the limit .BR AIO_MAX to be exceeded. .TP .B EINTR .I mode was .BR LIO_WAIT and a signal was caught before all I/O operations completed; see .BR signal (7). (This may even be one of the signals used for asynchronous I/O completion notification.) .TP .B EINVAL .I mode is invalid, or .\" Doesn't happen in glibc(?) .I nitems exceeds the limit .BR AIO_LISTIO_MAX . .TP .B EIO One of more of the operations specified by .IR aiocb_list failed. .\" e.g., ioa_reqprio or aio_lio_opcode was invalid The application can check the status of each operation using .BR aio_return (3). .PP If .BR lio_listio () fails with the error .BR EAGAIN , .BR EINTR , or .BR EIO , then some of the operations in .IR aiocb_list may have been initiated. If .BR lio_listio () fails for any other reason, then none of the I/O operations has been initiated. .SH VERSIONS The .BR lio_listio () function is available since glibc 2.1. .SH ATTRIBUTES For an explanation of the terms used in this section, see .BR attributes (7). .TS allbox; lb lb lb l l l. Interface Attribute Value T{ .BR lio_listio () T} Thread safety MT-Safe .TE .sp 1 .SH CONFORMING TO POSIX.1-2001, POSIX.1-2008. .SH 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 .\" or the control block of the operation must not be accessed during the operations or undefined results may occur. The memory areas involved must remain valid. .PP Simultaneous I/O operations specifying the same .I aiocb structure produce undefined results. .SH SEE ALSO .BR aio_cancel (3), .BR aio_error (3), .BR aio_fsync (3), .BR aio_return (3), .BR aio_suspend (3), .BR aio_write (3), .BR aio (7) .SH COLOPHON This page is part of release 4.16 of the Linux .I 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/.