The Open Group Base Specifications Issue 6
IEEE Std 1003.1, 2004 Edition
Copyright © 2001-2004 The IEEE and The Open Group, All Rights reserved.
A newer edition of this document exists here


fputwc - put a wide-character code on a stream


#include <stdio.h>
#include <wchar.h>

wint_t fputwc(wchar_t
wc, FILE *stream);


[CX] [Option Start] 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 IEEE Std 1003.1-2001 defers to the ISO C standard. [Option End]

The fputwc() function shall write the character corresponding to the wide-character code wc to the output stream pointed to by stream, at the position indicated by the associated file-position indicator for the stream (if defined), and advances the indicator appropriately. If the file cannot support positioning requests, or if the stream was opened with append mode, the character is appended to the output stream. If an error occurs while writing the character, the shift state of the output file is left in an undefined state.

[CX] [Option Start] The st_ctime and st_mtime fields of the file shall be marked for update between the successful execution of fputwc() and the next successful completion of a call to fflush() or fclose() on the same stream or a call to exit() or abort(). [Option End]


Upon successful completion, fputwc() shall return wc. Otherwise, it shall return WEOF, the error indicator for the stream shall be set, [CX] [Option Start]  and errno shall be set to indicate the error. [Option End]


The fputwc() function shall fail if either the stream is unbuffered or data in the stream's buffer needs to be written, and:

[CX] [Option Start] The O_NONBLOCK flag is set for the file descriptor underlying stream and the thread would be delayed in the write operation. [Option End]
[CX] [Option Start] The file descriptor underlying stream is not a valid file descriptor open for writing. [Option End]
[CX] [Option Start] An attempt was made to write to a file that exceeds the maximum file size or the process' file size limit. [Option End]
[CX] [Option Start] The file is a regular file and an attempt was made to write at or beyond the offset maximum associated with the corresponding stream. [Option End]
The wide-character code wc does not correspond to a valid character.
[CX] [Option Start] The write operation was terminated due to the receipt of a signal, and no data was transferred. [Option End]
[CX] [Option Start] A physical I/O error has occurred, or the process is a member of a background process group attempting to write to its controlling terminal, TOSTOP is set, the process is neither ignoring nor blocking SIGTTOU, and the process group of the process is orphaned. This error may also be returned under implementation-defined conditions. [Option End]
[CX] [Option Start] There was no free space remaining on the device containing the file. [Option End]
[CX] [Option Start] An attempt is made to write to a pipe or FIFO that is not open for reading by any process. A SIGPIPE signal shall also be sent to the thread. [Option End]

The fputwc() function may fail if:

[CX] [Option Start] Insufficient storage space is available. [Option End]
[CX] [Option Start] A request was made of a nonexistent device, or the request was outside the capabilities of the device. [Option End]

The following sections are informative.










ferror(), fopen(), setbuf() , ulimit(), the Base Definitions volume of IEEE Std 1003.1-2001, <stdio.h>, <wchar.h>


First released in Issue 4. Derived from the MSE working draft.

Issue 5

Aligned with ISO/IEC 9899:1990/Amendment 1:1995 (E). Specifically, the type of argument wc is changed from wint_t to wchar_t.

The Optional Header (OH) marking is removed from <stdio.h>.

Large File Summit extensions are added.

Issue 6

Extensions beyond the ISO C standard are marked.

The following new requirements on POSIX implementations derive from alignment with the Single UNIX Specification:

IEEE Std 1003.1-2001/Cor 2-2004, item XSH/TC2/D6/38 is applied, updating the [EAGAIN] error in the ERRORS section from ``the process would be delayed'' to ``the thread would be delayed''.

End of informative text.

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