1FGETWC(3P) POSIX Programmer's Manual FGETWC(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
13 fgetwc — get a wide-character code from a stream
14
16 #include <stdio.h>
17 #include <wchar.h>
18 wint_t fgetwc(FILE *stream);
20
22 The functionality described on this reference page is aligned with the
23 ISO C standard. Any conflict between the requirements described here
24 and the ISO C standard is unintentional. This volume of POSIX.1‐2008
25 defers to the ISO C standard.
26 The fgetwc() function shall obtain the next character (if present) from
28 the input stream pointed to by stream, convert that to the correspond‐
29 ing wide-character code, and advance the associated file position indi‐
30 cator for the stream (if defined).
31 If an error occurs, the resulting value of the file position indicator
33 for the stream is unspecified.
34 The fgetwc() function may mark the last data access timestamp of the
36 file associated with stream for update. The last data access timestamp
37 shall be marked for update by the first successful execution of
38 fgetwc(), fgetws(), fwscanf(), getwc(), getwchar(), vfwscanf(), vws‐
39 canf(), or wscanf() using stream that returns data not supplied by a
40 prior call to ungetwc().
41 The fgetwc() function shall not change the setting of errno if success‐
43 ful.
44
46 Upon successful completion, the fgetwc() function shall return the
47 wide-character code of the character read from the input stream pointed
48 to by stream converted to a type wint_t. If the end-of-file indicator
49 for the stream is set, or if the stream is at end-of-file, the end-of-
50 file indicator for the stream shall be set and fgetwc() shall return
51 WEOF. If a read error occurs, the error indicator for the stream shall
52 be set, fgetwc() shall return WEOF, and shall set errno to indicate the
53 error. If an encoding error occurs, the error indicator for the stream
54 shall be set, fgetwc() shall return WEOF, and shall set errno to indi‐
55 cate the error.
56
58 The fgetwc() function shall fail if data needs to be read and:
59 EAGAIN The O_NONBLOCK flag is set for the file descriptor underlying
61 stream and the thread would be delayed in the fgetwc() opera‐
62 tion.
63 EBADF The file descriptor underlying stream is not a valid file
65 descriptor open for reading.
66 EILSEQ The data obtained from the input stream does not form a valid
68 character.
69 EINTR The read 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 in a back‐
74 ground process group attempting to read from its controlling
75 terminal, and either the calling thread is blocking SIGTTIN or
76 the process is ignoring SIGTTIN or the process group of the
77 process is orphaned. This error may also be generated for
78 implementation-defined reasons.
79 EOVERFLOW
81 The file is a regular file and an attempt was made to read at or
82 beyond the offset maximum associated with the corresponding
83 stream.
84 The fgetwc() function may fail if:
86 ENOMEM Insufficient storage space is available.
88 ENXIO A request was made of a nonexistent device, or the request was
90 outside the capabilities of the device.
91 The following sections are informative.
93
95 None.
96
98 The ferror() or feof() functions must be used to distinguish between an
99 error condition and an end-of-file condition.
100
102 None.
103
105 None.
106
108 Section 2.5, Standard I/O Streams, feof(), ferror(), fopen()
109 The Base Definitions volume of POSIX.1‐2008, <stdio.h>, <wchar.h>
111
113 Portions of this text are reprinted and reproduced in electronic form
114 from IEEE Std 1003.1, 2013 Edition, Standard for Information Technology
115 -- Portable Operating System Interface (POSIX), The Open Group Base
116 Specifications Issue 7, Copyright (C) 2013 by the Institute of Electri‐
117 cal and Electronics Engineers, Inc and The Open Group. (This is
118 POSIX.1-2008 with the 2013 Technical Corrigendum 1 applied.) In the
119 event of any discrepancy between this version and the original IEEE and
120 The Open Group Standard, the original IEEE and The Open Group Standard
121 is the referee document. The original Standard can be obtained online
122 at http://www.unix.org/online.html .
123 Any typographical or formatting errors that appear in this page are
125 most likely to have been introduced during the conversion of the source
126 files to man page format. To report such errors, see https://www.ker‐
127 nel.org/doc/man-pages/reporting_bugs.html .
128IEEE/The Open Group 2013 FGETWC(3P)