1POSIX_FALLOCATE(3P) POSIX Programmer's Manual POSIX_FALLOCATE(3P)
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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.
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13 posix_fallocate — file space control (ADVANCED REALTIME)
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16 #include <fcntl.h>
17 int posix_fallocate(int fd, off_t offset, off_t len);
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21 The posix_fallocate() function shall ensure that any required storage
22 for regular file data starting at offset and continuing for len bytes
23 is allocated on the file system storage media. If posix_fallocate()
24 returns successfully, subsequent writes to the specified file data
25 shall not fail due to the lack of free space on the file system storage
26 media.
27 If the offset+len is beyond the current file size, then posix_fallo‐
29 cate() shall adjust the file size to offset+len. Otherwise, the file
30 size shall not be changed.
31 It is implementation-defined whether a previous posix_fadvise() call
33 influences allocation strategy.
34 Space allocated via posix_fallocate() shall be freed by a successful
36 call to creat() or open() that truncates the size of the file. Space
37 allocated via posix_fallocate() may be freed by a successful call to
38 ftruncate() that reduces the file size to a size smaller than off‐
39 set+len.
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42 Upon successful completion, posix_fallocate() shall return zero; other‐
43 wise, an error number shall be returned to indicate the error.
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46 The posix_fallocate() function shall fail if:
47 EBADF The fd argument is not a valid file descriptor.
49 EBADF The fd argument references a file that was opened without write
51 permission.
52 EFBIG The value of offset+len is greater than the maximum file size.
54 EINTR A signal was caught during execution.
56 EINVAL The len argument is less than zero, or the offset argument is
58 less than zero, or the underlying file system does not support
59 this operation.
60 EIO An I/O error occurred while reading from or writing to a file
62 system.
63 ENODEV The fd argument does not refer to a regular file.
65 ENOSPC There is insufficient free space remaining on the file system
67 storage media.
68 ESPIPE The fd argument is associated with a pipe or FIFO.
70 The posix_fallocate() function may fail if:
72 EINVAL The len argument is zero.
74 The following sections are informative.
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78 None.
79
81 The posix_fallocate() function is part of the Advisory Information
82 option and need not be provided on all implementations.
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85 None.
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88 None.
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91 creat(), ftruncate(), open(), unlink()
92 The Base Definitions volume of POSIX.1‐2008, <fcntl.h>
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96 Portions of this text are reprinted and reproduced in electronic form
97 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
98 -- Portable Operating System Interface (POSIX), The Open Group Base
99 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
100 cal and Electronics Engineers, Inc and The Open Group. (This is
101 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
102 event of any discrepancy between this version and the original IEEE and
103 The Open Group Standard, the original IEEE and The Open Group Standard
104 is the referee document. The original Standard can be obtained online
105 at http://www.unix.org/online.html .
106 Any typographical or formatting errors that appear in this page are
108 most likely to have been introduced during the conversion of the source
109 files to man page format. To report such errors, see https://www.ker‐
110 nel.org/doc/man-pages/reporting_bugs.html .
111IEEE/The Open Group 2013 POSIX_FALLOCATE(3P)