UTF8_putc
len = UTF8_putc(NULL, -1, value);
ret = UTF8_putc(*p, 0xff, value);
int utflen = UTF8_putc(utfbuf, sizeof(utfbuf), c);
return UTF8_putc((unsigned char *)str, 4, utf32chr);
int UTF8_putc(unsigned char *str, int len, unsigned long value);