1FSETPOS(3P) POSIX Programmer's Manual FSETPOS(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 fsetpos — set current file position
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15 #include <stdio.h>
16 int fsetpos(FILE *stream, const fpos_t *pos);
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20 The functionality described on this reference page is aligned with the
21 ISO C standard. Any conflict between the requirements described here
22 and the ISO C standard is unintentional. This volume of POSIX.1‐2017
23 defers to the ISO C standard.
24 The fsetpos() function shall set the file position and state indicators
26 for the stream pointed to by stream according to the value of the
27 object pointed to by pos, which the application shall ensure is a value
28 obtained from an earlier call to fgetpos() on the same stream. If a
29 read or write error occurs, the error indicator for the stream shall be
30 set and fsetpos() fails.
31 A successful call to the fsetpos() function shall clear the end-of-file
33 indicator for the stream and undo any effects of ungetc() on the same
34 stream. After an fsetpos() call, the next operation on an update stream
35 may be either input or output.
36 The behavior of fsetpos() on devices which are incapable of seeking is
38 implementation-defined. The value of the file offset associated with
39 such a device is undefined.
40 The fsetpos() function shall not change the setting of errno if suc‐
42 cessful.
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45 The fsetpos() function shall return 0 if it succeeds; otherwise, it
46 shall return a non-zero value and set errno to indicate the error.
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49 The fsetpos() function shall fail if, either the stream is unbuffered
50 or the stream's buffer needed to be flushed, and the call to fsetpos()
51 causes an underlying lseek() or write() to be invoked, and:
52 EAGAIN The O_NONBLOCK flag is set for the file descriptor and the
54 thread would be delayed in the write operation.
55 EBADF The file descriptor underlying the stream file is not open for
57 writing or the stream's buffer needed to be flushed and the file
58 is not open.
59 EFBIG An attempt was made to write a file that exceeds the maximum
61 file size.
62 EFBIG An attempt was made to write a file that exceeds the file size
64 limit of the process.
65 EFBIG The file is a regular file and an attempt was made to write at
67 or beyond the offset maximum associated with the corresponding
68 stream.
69 EINTR The write operation was terminated due to the receipt of a sig‐
71 nal, and no data was transferred.
72 EIO A physical I/O error has occurred, or the process is a member of
74 a background process group attempting to perform a write() to
75 its controlling terminal, TOSTOP is set, the calling thread is
76 not blocking SIGTTOU, the process is not ignoring SIGTTOU, and
77 the process group of the process is orphaned. This error may
78 also be returned under implementation-defined conditions.
79 ENOSPC There was no free space remaining on the device containing the
81 file.
82 EPIPE An attempt was made to write to a pipe or FIFO that is not open
84 for reading by any process; a SIGPIPE signal shall also be sent
85 to the thread.
86 ESPIPE The file descriptor underlying stream is associated with a pipe,
88 FIFO, or socket.
89 The fsetpos() function may fail if:
91 ENXIO A request was made of a nonexistent device, or the request was
93 outside the capabilities of the device.
94 The following sections are informative.
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98 None.
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101 None.
102
104 None.
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107 None.
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110 Section 2.5, Standard I/O Streams, fopen(), ftell(), lseek(), rewind(),
111 ungetc(), write()
112 The Base Definitions volume of POSIX.1‐2017, <stdio.h>
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116 Portions of this text are reprinted and reproduced in electronic form
117 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
118 table Operating System Interface (POSIX), The Open Group Base Specifi‐
119 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
120 Electrical and Electronics Engineers, Inc and The Open Group. In the
121 event of any discrepancy between this version and the original IEEE and
122 The Open Group Standard, the original IEEE and The Open Group Standard
123 is the referee document. The original Standard can be obtained online
124 at http://www.opengroup.org/unix/online.html .
125 Any typographical or formatting errors that appear in this page are
127 most likely to have been introduced during the conversion of the source
128 files to man page format. To report such errors, see https://www.ker‐
129 nel.org/doc/man-pages/reporting_bugs.html .
130IEEE/The Open Group 2017 FSETPOS(3P)