mbsrtowcs - convert multi-byte string to wide-character string

Syntax	#include <wchar.h> size_t mbsrtowcs(wchar_t *dst, const char **src, size_t len, mbstate_t *ps);
Description	mbsrtowcs() converts a sequence of multi-byte characters in the array indirectly pointed to by src to wide characters. mbsrtowcs() starts the conversion with the conversion state described in *ps. The converted characters are written to the array pointed to by dst as long as dst is not a null pointer. Every character is converted as if the mbrtowc() was called. The conversion terminates when a terminating null character is encountered. The null character is also converted and written into the array. The conversion is terminated abnormally if a sequence of bytes is found that does not represent a valid multi-byte character or dst is not a null pointer and len characters were written into the array pointed to by dst. If dst is not a null pointer, the pointer object pointed to by src is assigned one of the following two values: a null pointer if the conversion terminated when it reached a null character the address directly after the last multi-byte character converted If dst is not a null pointer and the conversion terminated when it reached a null character, then the final state is the same as the “initial conversion” state.
Return val.	The number of successfully converted multi-byte characters.
		if successful. The terminating null character (if present) is not counted.
	(size_t)-1	if a conversion error occurred, i.e. a sequence of bytes that does not represent a valid multi-byte character was found. The value of the EILSEQ macro is written in errno. The conversion status is undefined.
See also	mblen(), mbtowc(), wcstombs(), wctomb().