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
12 fgetwc — get a wide-character code from a stream
13
15 #include <stdio.h>
16 #include <wchar.h>
17 wint_t fgetwc(FILE *stream);
19
21 The functionality described on this reference page is aligned with the
22 ISO C standard. Any conflict between the requirements described here
23 and the ISO C standard is unintentional. This volume of POSIX.1‐2017
24 defers to the ISO C standard.
25 The fgetwc() function shall obtain the next character (if present) from
27 the input stream pointed to by stream, convert that to the correspond‐
28 ing wide-character code, and advance the associated file position indi‐
29 cator for the stream (if defined).
30 If an error occurs, the resulting value of the file position indicator
32 for the stream is unspecified.
33 The fgetwc() function may mark the last data access timestamp of the
35 file associated with stream for update. The last data access timestamp
36 shall be marked for update by the first successful execution of
37 fgetwc(), fgetws(), fwscanf(), getwc(), getwchar(), vfwscanf(), vws‐
38 canf(), or wscanf() using stream that returns data not supplied by a
39 prior call to ungetwc().
40 The fgetwc() function shall not change the setting of errno if success‐
42 ful.
43
45 Upon successful completion, the fgetwc() function shall return the
46 wide-character code of the character read from the input stream pointed
47 to by stream converted to a type wint_t. If the end-of-file indicator
48 for the stream is set, or if the stream is at end-of-file, the end-of-
49 file indicator for the stream shall be set and fgetwc() shall return
50 WEOF. If a read error occurs, the error indicator for the stream shall
51 be set, fgetwc() shall return WEOF, and shall set errno to indicate the
52 error. If an encoding error occurs, the error indicator for the stream
53 shall be set, fgetwc() shall return WEOF, and shall set errno to indi‐
54 cate the error.
55
57 The fgetwc() function shall fail if data needs to be read and:
58 EAGAIN The O_NONBLOCK flag is set for the file descriptor underlying
60 stream and the thread would be delayed in the fgetwc() opera‐
61 tion.
62 EBADF The file descriptor underlying stream is not a valid file
64 descriptor open for reading.
65 EILSEQ The data obtained from the input stream does not form a valid
67 character.
68 EINTR The read operation was terminated due to the receipt of a sig‐
70 nal, and no data was transferred.
71 EIO A physical I/O error has occurred, or the process is in a back‐
73 ground process group attempting to read from its controlling
74 terminal, and either the calling thread is blocking SIGTTIN or
75 the process is ignoring SIGTTIN or the process group of the
76 process is orphaned. This error may also be generated for
77 implementation-defined reasons.
78 EOVERFLOW
80 The file is a regular file and an attempt was made to read at or
81 beyond the offset maximum associated with the corresponding
82 stream.
83 The fgetwc() function may fail if:
85 ENOMEM Insufficient storage space is available.
87 ENXIO A request was made of a nonexistent device, or the request was
89 outside the capabilities of the device.
90 The following sections are informative.
92
94 None.
95
97 The ferror() or feof() functions must be used to distinguish between an
98 error condition and an end-of-file condition.
99
101 None.
102
104 None.
105
107 Section 2.5, Standard I/O Streams, feof(), ferror(), fopen()
108 The Base Definitions volume of POSIX.1‐2017, <stdio.h>, <wchar.h>
110
112 Portions of this text are reprinted and reproduced in electronic form
113 from IEEE Std 1003.1-2017, Standard for Information Technology -- Por‐
114 table Operating System Interface (POSIX), The Open Group Base Specifi‐
115 cations Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of
116 Electrical and Electronics Engineers, Inc and The Open Group. In the
117 event of any discrepancy between this version and the original IEEE and
118 The Open Group Standard, the original IEEE and The Open Group Standard
119 is the referee document. The original Standard can be obtained online
120 at http://www.opengroup.org/unix/online.html .
121 Any typographical or formatting errors that appear in this page are
123 most likely to have been introduced during the conversion of the source
124 files to man page format. To report such errors, see https://www.ker‐
125 nel.org/doc/man-pages/reporting_bugs.html .
126IEEE/The Open Group 2017 FGETWC(3P)