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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:40:15 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:40:15 +0000 |
commit | 399644e47874bff147afb19c89228901ac39340e (patch) | |
tree | 1c4c0b733f4c16b5783b41bebb19194a9ef62ad1 /man3/aio_read.3 | |
parent | Initial commit. (diff) | |
download | manpages-399644e47874bff147afb19c89228901ac39340e.tar.xz manpages-399644e47874bff147afb19c89228901ac39340e.zip |
Adding upstream version 6.05.01.upstream/6.05.01
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'man3/aio_read.3')
-rw-r--r-- | man3/aio_read.3 | 160 |
1 files changed, 160 insertions, 0 deletions
diff --git a/man3/aio_read.3 b/man3/aio_read.3 new file mode 100644 index 0000000..909d444 --- /dev/null +++ b/man3/aio_read.3 @@ -0,0 +1,160 @@ +'\" t +.\" Copyright (c) 2003 Andries Brouwer (aeb@cwi.nl) +.\" +.\" SPDX-License-Identifier: GPL-2.0-or-later +.\" +.TH aio_read 3 2023-07-20 "Linux man-pages 6.05.01" +.SH NAME +aio_read \- asynchronous read +.SH LIBRARY +Real-time library +.RI ( librt ", " \-lrt ) +.SH SYNOPSIS +.nf +.B "#include <aio.h>" +.PP +.BI "int aio_read(struct aiocb *" aiocbp ); +.fi +.SH DESCRIPTION +The +.BR aio_read () +function queues the I/O request described by the buffer pointed to by +.IR aiocbp . +This function is the asynchronous analog of +.BR read (2). +The arguments of the call +.PP +.in +4n +.EX +read(fd, buf, count) +.EE +.in +.PP +correspond (in order) to the fields +.IR aio_fildes , +.IR aio_buf , +and +.I aio_nbytes +of the structure pointed to by +.IR aiocbp . +(See +.BR aio (7) +for a description of the +.I aiocb +structure.) +.PP +The data is read starting at the absolute position +.IR aiocbp\->aio_offset , +regardless of the file offset. +After the call, +the value of the file offset is unspecified. +.PP +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 +.BR aio_error (3). +The return status of a completed I/O operation can be obtained by +.BR aio_return (3). +Asynchronous notification of I/O completion can be obtained by setting +.I aiocbp\->aio_sigevent +appropriately; see +.BR sigevent (7) +for details. +.PP +If +.B _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 +.IR aiocbp\->aio_reqprio . +.PP +The field +.I aiocbp\->aio_lio_opcode +is ignored. +.PP +No data is read from a regular file beyond its maximum offset. +.SH RETURN VALUE +On success, 0 is returned. +On error, the request is not enqueued, \-1 +is returned, and +.I errno +is set to indicate the error. +If an error is detected only later, it will +be reported via +.BR aio_return (3) +(returns status \-1) and +.BR aio_error (3) +(error status\[em]whatever one would have gotten in +.IR errno , +such as +.BR EBADF ). +.SH ERRORS +.TP +.B EAGAIN +Out of resources. +.TP +.B EBADF +.I aio_fildes +is not a valid file descriptor open for reading. +.TP +.B EINVAL +One or more of +.IR aio_offset , +.IR aio_reqprio , +or +.I aio_nbytes +are invalid. +.TP +.B ENOSYS +.BR aio_read () +is not implemented. +.TP +.B 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. +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR aio_read () +T} Thread safety MT-Safe +.TE +.sp 1 +.SH STANDARDS +POSIX.1-2008. +.SH HISTORY +glibc 2.1. +POSIX.1-2001. +.SH NOTES +It is a good idea to zero out the control block before use. +The control block must not be changed while the read operation +is in progress. +The buffer area being read into +.\" or the control block of the operation +must not be accessed during the operation 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 EXAMPLES +See +.BR aio (7). +.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 lio_listio (3), +.BR aio (7) |