NAME

vfwprintf, vswprintf, vwprintf — wide-character formatted output of a stdarg argument list

SYNOPSIS

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

int vfwprintf(FILE *restrict stream, const wchar_t *restrict format,
       va_list arg);
int vswprintf(wchar_t *restrict ws, size_t n,
       const wchar_t *restrict format, va_list arg);
int vwprintf(const wchar_t *restrict format, va_list arg);


DESCRIPTION

^[CX] 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.1-2024 defers to the ISO C standard.

The vfwprintf(), vswprintf(), and vwprintf() functions shall be equivalent to fwprintf(), swprintf(), and wprintf() respectively, except that instead of being called with a variable number of arguments, they are called with an argument list as defined by <stdarg.h>.

These functions shall not invoke the va_end macro. However, as these functions do invoke the va_arg macro, the value of ap after the return is unspecified.

RETURN VALUE

Refer to fwprintf.

ERRORS

Refer to fwprintf.

EXAMPLES

None.

APPLICATION USAGE

Applications using these functions should call va_end(ap) afterwards to clean up.

RATIONALE

None.

FUTURE DIRECTIONS

None.

SEE ALSO

2.5 Standard I/O Streams, fwprintf

XBD <stdarg.h>, <stdio.h>, <wchar.h>

CHANGE HISTORY

First released in Issue 5. Included for alignment with ISO/IEC 9899:1990/Amendment 1:1995 (E).

Issue 6

The vfwprintf(), vswprintf(), and vwprintf() prototypes are updated for alignment with the ISO/IEC 9899:1999 standard.

Issue 7

POSIX.1-2008, Technical Corrigendum 1, XSH/TC1-2008/0705 [14] is applied.