C Programming/stdio.h/vwprintf

vwprintf is a C standard library function as defined in wchar.h .It has function signature as int vwprintf(const wchar t *format, va_list args);

In signature of function vwprintf, format is format specialisation and args is pointer to arguments.

comparision with other functions
The functioning of vwprintf is same as that of swprintf. The difference between both functions is that the argument list has been replaced by a pointer to a list of argument. vwprintf performs the wide character output to the string like stdout and stdout should not be byte oriented.

The functioning of vwprintf is same as that of swprintf.The difference between both functions is that the argument list has been replaced by a pointer to a list of argument. vwprintf performs the wide character output to the string like stdout and stdout should not be byte oriented. this function return the number of characters not including the null character and any negative value if an output error occurs vwprintf is equivalent to wprintf with argument list replaced by arg and which can be initialised by vastart macro.

return values
vwprintf returns number of characters written but excluding the NULL character on success.But on failure it returns an error and errno is set.