sprintf_s doesn't handle empty string correctly

[cliffwy]

call this function: sprintf_s(buff, sizeof(buff), "%s", "");
it gives error. because the call to "vsnprintf" returns 0. which is correct because it's printing empty string.

if (unlikely(ret <= 0)) {
        char errstr[128] = "sprintf_s: ";
        strcat(errstr, strerror(errno));
        handle_error(dest, dmax, errstr, -ret);
    }

[DBJDBJ]

The whole of ISO C does not handle the empty string. Correctly or not.

strlen("") == 0

""[0] == '\0' 

But then a lot of people have the same problem, thus stepping on others' toes. An example, from a different galaxy, but on the same subject.

Live with it™

😉

[rurban]

The _s extension defines what to do with an empty string and NULL, which I'm going to implement properly in the printf branch.
There were too many edge-cases not handled correctly.