c Programming/C Reference/wchar.h/swprintf

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swprintf is a C standard library function as defined in wchar.h and it's required header files are stdio.h and wchar.h. It has function signature as

'int swprintf(wchar_t *s,, size_t n, const wchar_t format,...);

n the signature of swprintf:
s : it is pointer to the buffer where you want to store the formatted string.The formatting string provides the extra arguments required
n : it is maximum number of characters to be stored in the buffer appending the null character.
format : this is the wide character string which shows the format of the output.


The swprintf function perform wide character output to an array of wide characters. The programmer must ensure that there is space for at least 'n' wide characters at 's'.


swprintf() is the function which prints the output after the null character in the consecutive wide character starting at *s.And it prints no n more characters up to next null character appears.swprintf is wide character version of sprintf.pointer arguments to swprintf are wide character string

return value[edit]

This function returns number of character written or -1 if an error exist.If s(pointer to buffer) or format is a null pointer ,invalid parameter is invoked.If the program allows to run this code the it returns -1 or errno is set to EINVAL. swprintf returns number of wide character which are stored in 's'(buffer) not counting the last null character.