fputws - Man Page

put a wide-character string on a stream


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.


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

int fputws(const wchar_t *restrict ws, FILE *restrict 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.

The fputws() function shall write a character string corresponding to the (null-terminated) wide-character string pointed to by ws to the stream pointed to by stream. No character corresponding to the terminating null wide-character code shall be written.

The last data modification and last file status change timestamps of the file shall be marked for update between the successful execution of fputws() and the next successful completion of a call to fflush() or fclose() on the same stream or a call to exit() or abort().

Return Value

Upon successful completion, fputws() shall return a non-negative number. Otherwise, it shall return -1, set an error indicator for the stream, and set errno to indicate the error.


Refer to fputwc().

The following sections are informative.



Application Usage

The fputws() function does not append a <newline>.

This volume of POSIX.1-2017 requires that successful completion simply return a non-negative integer. There are at least three known different implementation conventions for this requirement:


Return a constant value.


Return the last character written.


Return the number of bytes written. Note that this implementation convention cannot be adhered to for strings longer than {INT_MAX} bytes as the value would not be representable in the return type of the function. For backwards-compatibility, implementations can return the number of bytes for strings of up to {INT_MAX} bytes, and return {INT_MAX} for all longer strings.



Future Directions


See Also

Section 2.5, Standard I/O Streams, fopen()

The Base Definitions volume of POSIX.1-2017, <stdio.h>, <wchar.h>

Referenced By


2017 IEEE/The Open Group POSIX Programmer's Manual