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1 | .\" Copyright 2001 Andries Brouwer <aeb@cwi.nl>. |
2 | .\" | |
93015253 | 3 | .\" %%%LICENSE_START(VERBATIM) |
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4 | .\" Permission is granted to make and distribute verbatim copies of this |
5 | .\" manual provided the copyright notice and this permission notice are | |
6 | .\" preserved on all copies. | |
7 | .\" | |
8 | .\" Permission is granted to copy and distribute modified versions of this | |
9 | .\" manual under the conditions for verbatim copying, provided that the | |
10 | .\" entire resulting derived work is distributed under the terms of a | |
11 | .\" permission notice identical to this one. | |
c13182ef | 12 | .\" |
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13 | .\" Since the Linux kernel and libraries are constantly changing, this |
14 | .\" manual page may be incorrect or out-of-date. The author(s) assume no | |
15 | .\" responsibility for errors or omissions, or for damages resulting from | |
16 | .\" the use of the information contained herein. The author(s) may not | |
17 | .\" have taken the same level of care in the production of this manual, | |
18 | .\" which is licensed free of charge, as they might when working | |
19 | .\" professionally. | |
c13182ef | 20 | .\" |
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21 | .\" Formatted or processed versions of this manual, if unaccompanied by |
22 | .\" the source, must acknowledge the copyright and authors of this work. | |
4b72fb64 | 23 | .\" %%%LICENSE_END |
fea681da | 24 | .\" |
4b8c67d9 | 25 | .TH FSEEKO 3 2017-09-15 "" "Linux Programmer's Manual" |
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26 | .SH NAME |
27 | fseeko, ftello \- seek to or report file position | |
28 | .SH SYNOPSIS | |
29 | .nf | |
30 | .B #include <stdio.h> | |
68e4db0a | 31 | .PP |
fea681da | 32 | .BI "int fseeko(FILE *" stream ", off_t " offset ", int " whence ); |
68e4db0a | 33 | .PP |
fea681da | 34 | .BI "off_t ftello(FILE *" stream ); |
fea681da | 35 | .fi |
68e4db0a | 36 | .PP |
aba863af MK |
37 | .in -4n |
38 | Feature Test Macro Requirements for glibc (see | |
39 | .BR feature_test_macros (7)): | |
40 | .in | |
68e4db0a | 41 | .PP |
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42 | .BR fseeko (), |
43 | .BR ftello (): | |
44 | .br | |
45 | .RS 4 | |
46 | .ad l | |
a446ac0c | 47 | _FILE_OFFSET_BITS\ ==\ 64 || _POSIX_C_SOURCE\ >=\ 200112L |
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48 | .br |
49 | (defining the obsolete _LARGEFILE_SOURCE macro also works) | |
50 | .RE | |
51 | .ad | |
fea681da | 52 | .SH DESCRIPTION |
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53 | The |
54 | .BR fseeko () | |
55 | and | |
56 | .BR ftello () | |
57 | functions are identical to | |
58 | .BR fseek (3) | |
59 | and | |
60 | .BR ftell (3) | |
61 | (see | |
fea681da | 62 | .BR fseek (3)), |
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63 | respectively, except that the |
64 | .I offset | |
65 | argument of | |
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66 | .BR fseeko () |
67 | and the return value of | |
68 | .BR ftello () | |
c6fa0841 MK |
69 | is of type |
70 | .I off_t | |
71 | instead of | |
72 | .IR long . | |
dd3568a1 | 73 | .PP |
1f63d3ec | 74 | On some architectures, both |
51700fd7 | 75 | .IR off_t |
c6fa0841 MK |
76 | and |
77 | .I long | |
1f63d3ec MK |
78 | are 32-bit types, but defining |
79 | .BR _FILE_OFFSET_BITS | |
80 | with the value 64 (before including | |
81 | .I any | |
82 | header files) | |
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83 | will turn |
84 | .I off_t | |
85 | into a 64-bit type. | |
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86 | .SH RETURN VALUE |
87 | On successful completion, | |
88 | .BR fseeko () | |
89 | returns 0, while | |
90 | .BR ftello () | |
91 | returns the current offset. | |
c13182ef | 92 | Otherwise, \-1 is returned and |
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93 | .I errno |
94 | is set to indicate the error. | |
95 | .SH ERRORS | |
96 | See the ERRORS in | |
97 | .BR fseek (3). | |
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98 | .SH VERSIONS |
99 | These functions are available under glibc since version 2.1. | |
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100 | .SH ATTRIBUTES |
101 | For an explanation of the terms used in this section, see | |
102 | .BR attributes (7). | |
103 | .TS | |
104 | allbox; | |
105 | lbw18 lb lb | |
106 | l l l. | |
107 | Interface Attribute Value | |
108 | T{ | |
109 | .BR fseeko (), | |
110 | .BR ftello () | |
111 | T} Thread safety MT-Safe | |
112 | .TE | |
847e0d88 | 113 | .sp 1 |
47297adb | 114 | .SH CONFORMING TO |
a0c1affc | 115 | POSIX.1-2001, POSIX.1-2008, SUSv2. |
47297adb | 116 | .SH SEE ALSO |
fea681da | 117 | .BR fseek (3) |