strfmon
ssize_t strfmon(char * __restrict, size_t, const char * __restrict, ...)
strfmon(actual, sizeof(actual) - 1, "%i", n);
strfmon(actual, sizeof(actual) - 1, format,
strfmon(buf, sizeof(buf) - 1, "[%n] ", -123.0);
strfmon(buf, sizeof(buf) - 1, "[%n] ", -123.0);
strfmon(actual, sizeof(actual) - 1, "[%i]", 123.45);
strfmon(string, sizeof(string), "[%8n] [%8n]", 123.45, 123.45);