1AIO_WRITE(3P) POSIX Programmer's Manual AIO_WRITE(3P)
2
6 This manual page is part of the POSIX Programmer's Manual. The Linux
7 implementation of this interface may differ (consult the corresponding
8 Linux manual page for details of Linux behavior), or the interface may
9 not be implemented on Linux.
10
12 aio_write — asynchronous write to a file
13
15 #include <aio.h>
16 int aio_write(struct aiocb *aiocbp);
18
20 The aio_write() function shall write aiocbp->aio_nbytes to the file
21 associated with aiocbp->aio_fildes from the buffer pointed to by
22 aiocbp->aio_buf. The function shall return when the write request has
23 been initiated or, at a minimum, queued to the file or device.
24 If prioritized I/O is supported for this file, then the asynchronous
26 operation shall be submitted at a priority equal to a base scheduling
27 priority minus aiocbp->aio_reqprio. If Thread Execution Scheduling is
28 not supported, then the base scheduling priority is that of the calling
29 process;
30 otherwise, the base scheduling priority is that of the calling thread.
31 The aiocbp argument may be used as an argument to aio_error() and
33 aio_return() in order to determine the error status and return status,
34 respectively, of the asynchronous operation while it is proceeding.
35 The aiocbp argument points to an aiocb structure. If the buffer pointed
37 to by aiocbp->aio_buf or the control block pointed to by aiocbp becomes
38 an illegal address prior to asynchronous I/O completion, then the
39 behavior is undefined.
40 If O_APPEND is not set for the file descriptor aio_fildes, then the
42 requested operation shall take place at the absolute position in the
43 file as given by aio_offset, as if lseek() were called immediately
44 prior to the operation with an offset equal to aio_offset and a whence
45 equal to SEEK_SET. If O_APPEND is set for the file descriptor, or if
46 aio_fildes is associated with a device that is incapable of seeking,
47 write operations append to the file in the same order as the calls were
48 made, except under circumstances described in Section 2.8.2, Asynchro‐
49 nous I/O. After a successful call to enqueue an asynchronous I/O oper‐
50 ation, the value of the file offset for the file is unspecified.
51 The aio_sigevent member specifies the notification which occurs when
53 the request is completed.
54 The aiocbp->aio_lio_opcode field shall be ignored by aio_write().
56 Simultaneous asynchronous operations using the same aiocbp produce
58 undefined results.
59 If synchronized I/O is enabled on the file associated with
61 aiocbp->aio_fildes, the behavior of this function shall be according to
62 the definitions of synchronized I/O data integrity completion, and syn‐
63 chronized I/O file integrity completion.
64 For any system action that changes the process memory space while an
66 asynchronous I/O is outstanding to the address range being changed, the
67 result of that action is undefined.
68 For regular files, no data transfer shall occur past the offset maximum
70 established in the open file description associated with
71 aiocbp->aio_fildes.
72
74 The aio_write() function shall return the value zero if the I/O opera‐
75 tion is successfully queued; otherwise, the function shall return the
76 value -1 and set errno to indicate the error.
77
79 The aio_write() function shall fail if:
80 EAGAIN The requested asynchronous I/O operation was not queued due to
82 system resource limitations.
83 Each of the following conditions may be detected synchronously at the
85 time of the call to aio_write(), or asynchronously. If any of the con‐
86 ditions below are detected synchronously, the aio_write() function
87 shall return -1 and set errno to the corresponding value. If any of the
88 conditions below are detected asynchronously, the return status of the
89 asynchronous operation shall be set to -1, and the error status of the
90 asynchronous operation is set to the corresponding value.
91 EBADF The aiocbp->aio_fildes argument is not a valid file descriptor
93 open for writing.
94 EINVAL The file offset value implied by aiocbp->aio_offset would be
96 invalid,
97 aiocbp->aio_reqprio is not a valid value, or aiocbp->aio_nbytes
98 is an invalid value.
99 In the case that the aio_write() successfully queues the I/O operation,
101 the return status of the asynchronous operation shall be one of the
102 values normally returned by the write() function call. If the operation
103 is successfully queued but is subsequently canceled or encounters an
104 error, the error status for the asynchronous operation contains one of
105 the values normally set by the write() function call, or one of the
106 following:
107 EBADF The aiocbp->aio_fildes argument is not a valid file descriptor
109 open for writing.
110 EINVAL The file offset value implied by aiocbp->aio_offset would be
112 invalid.
113 ECANCELED
115 The requested I/O was canceled before the I/O completed due to
116 an explicit aio_cancel() request.
117 The following condition may be detected synchronously or asyn‐
119 chronously:
120 EFBIG The file is a regular file, aiobcp->aio_nbytes is greater than
122 0, and the starting offset in aiobcp->aio_offset is at or beyond
123 the offset maximum in the open file description associated with
124 aiocbp->aio_fildes.
125 The following sections are informative.
127
129 None.
130
132 None.
133
135 None.
136
138 None.
139
141 Section 2.8.2, Asynchronous I/O, aio_cancel(), aio_error(), aio_read(),
142 aio_return(), close(), exec, exit(), fork(), lio_listio(), lseek(),
143 write()
144 The Base Definitions volume of POSIX.1‐2017, <aio.h>
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148 Portions of this text are reprinted and reproduced in electronic form
149 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
150 table Operating System Interface (POSIX), The Open Group Base Specifi‐
151 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
152 Electrical and Electronics Engineers, Inc and The Open Group. In the
153 event of any discrepancy between this version and the original IEEE and
154 The Open Group Standard, the original IEEE and The Open Group Standard
155 is the referee document. The original Standard can be obtained online
156 at http://www.opengroup.org/unix/online.html .
157 Any typographical or formatting errors that appear in this page are
159 most likely to have been introduced during the conversion of the source
160 files to man page format. To report such errors, see https://www.ker‐
161 nel.org/doc/man-pages/reporting_bugs.html .
162IEEE/The Open Group 2017 AIO_WRITE(3P)