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PROLOG |NAME |SYNOPSIS |DESCRIPTION |RETURN VALUE |ERRORS |EXAMPLES |APPLICATION USAGE |RATIONALE |FUTURE DIRECTIONS |SEE ALSO |COPYRIGHT | |
FGETWC(3P) POSIX Programmer's ManualFGETWC(3P)This manual page is part of the POSIX Programmer's Manual. The Linux implementation of this interface may differ (consult the corresponding Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.
fgetwc — get a wide-character code from a stream
#include <stdio.h> #include <wchar.h> wint_t fgetwc(FILE *stream);
The functionality described on this reference page is aligned with the ISO C standard. Any conflict between the requirements described here and the ISO C standard is unintentional. This volume of POSIX.1‐2017 defers to the ISO C standard. Thefgetwc() function shall obtain the next character (if present) from the input stream pointed to bystream, convert that to the corresponding wide-character code, and advance the associated file position indicator for the stream (if defined). If an error occurs, the resulting value of the file position indicator for the stream is unspecified. Thefgetwc() function may mark the last data access timestamp of the file associated withstream for update. The last data access timestamp shall be marked for update by the first successful execution offgetwc(),fgetws(),fwscanf(),getwc(),getwchar(),vfwscanf(),vwscanf(), orwscanf() usingstream that returns data not supplied by a prior call toungetwc(). Thefgetwc() function shall not change the setting oferrno if successful.
Upon successful completion, thefgetwc() function shall return the wide-character code of the character read from the input stream pointed to bystream converted to a typewint_t. If the end-of- file indicator for the stream is set, or if the stream is at end- of-file, the end-of-file indicator for the stream shall be set andfgetwc() shall return WEOF. If a read error occurs, the error indicator for the stream shall be set,fgetwc() shall return WEOF, and shall seterrno to indicate the error. If an encoding error occurs, the error indicator for the stream shall be set,fgetwc() shall return WEOF, and shall seterrno to indicate the error.
Thefgetwc() function shall fail if data needs to be read and:EAGAINThe O_NONBLOCK flag is set for the file descriptor underlyingstream and the thread would be delayed in thefgetwc() operation.EBADFThe file descriptor underlyingstream is not a valid file descriptor open for reading.EILSEQThe data obtained from the input stream does not form a valid character.EINTRThe read operation was terminated due to the receipt of a signal, and no data was transferred.EIOA physical I/O error has occurred, or the process is in a background process group attempting to read from its controlling terminal, and either the calling thread is blocking SIGTTIN or the process is ignoring SIGTTIN or the process group of the process is orphaned. This error may also be generated for implementation-defined reasons.EOVERFLOW The file is a regular file and an attempt was made to read at or beyond the offset maximum associated with the corresponding stream. Thefgetwc() function may fail if:ENOMEMInsufficient storage space is available.ENXIOA request was made of a nonexistent device, or the request was outside the capabilities of the device.The following sections are informative.
None.
Theferror() orfeof() functions must be used to distinguish between an error condition and an end-of-file condition.
None.
None.
Section 2.5,Standard I/O Streams,feof(3p),ferror(3p),fopen(3p) The Base Definitions volume of POSIX.1‐2017,stdio.h(0p),wchar.h(0p)
Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1-2017, Standard for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifications Issue 7, 2018 Edition, Copyright (C) 2018 by the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the event of any discrepancy between this version and the original IEEE and The Open Group Standard, the original IEEE and The Open Group Standard is the referee document. The original Standard can be obtained online athttp://www.opengroup.org/unix/online.html . Any typographical or formatting errors that appear in this page are most likely to have been introduced during the conversion of the source files to man page format. To report such errors, seehttps://www.kernel.org/doc/man-pages/reporting_bugs.html .IEEE/The Open Group 2017FGETWC(3P)Pages that refer to this page:wchar.h(0p), fgetws(3p), fscanf(3p), fwscanf(3p), getwc(3p), getwchar(3p)
HTML rendering created 2025-09-06 byMichael Kerrisk, author ofThe Linux Programming Interface. For details of in-depthLinux/UNIX system programming training courses that I teach, lookhere. Hosting byjambit GmbH. | |