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f50f6cb5 | 1 | .\" Copyright (c) 2006, Michael Kerrisk <mtk.manpages@gmail.com> |
1cd27447 | 2 | .\" |
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1cd27447 | 24 | .\" |
4b8c67d9 | 25 | .TH POSIX_FALLOCATE 3 2017-09-15 "GNU" "Linux Programmer's Manual" |
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26 | .SH NAME |
27 | posix_fallocate \- allocate file space | |
28 | .SH SYNOPSIS | |
29 | .nf | |
063a2574 | 30 | .B #include <fcntl.h> |
68e4db0a | 31 | .PP |
1cd27447 | 32 | .BI "int posix_fallocate(int " fd ", off_t " offset ", off_t " len ); |
1cd27447 | 33 | .fi |
68e4db0a | 34 | .PP |
9a30939e MK |
35 | .ad l |
36 | .in -4n | |
37 | Feature Test Macro Requirements for glibc (see | |
38 | .BR feature_test_macros (7)): | |
39 | .in | |
68e4db0a | 40 | .PP |
9a30939e MK |
41 | .BR posix_fallocate (): |
42 | .RS 4 | |
a446ac0c | 43 | _POSIX_C_SOURCE\ >=\ 200112L |
9a30939e MK |
44 | .RE |
45 | .ad | |
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46 | .SH DESCRIPTION |
47 | The function | |
48 | .BR posix_fallocate () | |
49 | ensures that disk space is allocated for the file referred to by the | |
d9cb0d7d | 50 | file descriptor |
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51 | .I fd |
52 | for the bytes in the range starting at | |
0daa9e92 | 53 | .I offset |
c13182ef | 54 | and continuing for |
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55 | .I len |
56 | bytes. | |
57 | After a successful call to | |
58 | .BR posix_fallocate (), | |
59 | subsequent writes to bytes in the specified range are | |
60 | guaranteed not to fail because of lack of disk space. | |
847e0d88 | 61 | .PP |
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62 | If the size of the file is less than |
63 | .IR offset + len , | |
64 | then the file is increased to this size; | |
65 | otherwise the file size is left unchanged. | |
47297adb | 66 | .SH RETURN VALUE |
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67 | .BR posix_fallocate () |
68 | returns zero on success, or an error number on failure. | |
69 | Note that | |
0daa9e92 | 70 | .I errno |
1cd27447 | 71 | is not set. |
47297adb | 72 | .SH ERRORS |
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73 | .TP |
74 | .B EBADF | |
75 | .I fd | |
76 | is not a valid file descriptor, or is not opened for writing. | |
77 | .TP | |
78 | .B EFBIG | |
79 | .I offset+len | |
80 | exceeds the maximum file size. | |
81 | .TP | |
3fe3c87e MK |
82 | .B EINTR |
83 | A signal was caught during execution. | |
84 | .TP | |
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85 | .B EINVAL |
86 | .I offset | |
0c4dba93 | 87 | was less than 0, or |
1cd27447 | 88 | .I len |
a74bc4c9 CD |
89 | was less than or equal to 0, or the underlying filesystem does not |
90 | support the operation. | |
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91 | .TP |
92 | .B ENODEV | |
93 | .I fd | |
94 | does not refer to a regular file. | |
95 | .TP | |
96 | .B ENOSPC | |
c13182ef | 97 | There is not enough space left on the device containing the file |
1cd27447 | 98 | referred to by |
4df883b9 | 99 | .IR fd . |
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100 | .TP |
101 | .B ESPIPE | |
102 | .I fd | |
681445c1 | 103 | refers to a pipe. |
a759cc87 | 104 | .SH VERSIONS |
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105 | .BR posix_fallocate () |
106 | is available since glibc 2.1.94. | |
955269b4 | 107 | .SH ATTRIBUTES |
83336152 PH |
108 | For an explanation of the terms used in this section, see |
109 | .BR attributes (7). | |
110 | .TS | |
111 | allbox; | |
112 | lb lb lb | |
113 | l l l. | |
114 | Interface Attribute Value | |
115 | T{ | |
955269b4 | 116 | .BR posix_fallocate () |
624fbe44 | 117 | T} Thread safety MT-Safe (but see NOTES) |
83336152 | 118 | .TE |
47297adb | 119 | .SH CONFORMING TO |
1cd27447 | 120 | POSIX.1-2001. |
847e0d88 | 121 | .PP |