Is there a d analog of strncmp?

[dan via Digitalmars-d-learn]

In c, there's this very nice function strncmp(s1,s2,count) which 
compares two c strings, using at most count characters.  count 
can be less than, more than, or equal to either or both of the 
lengths of the two strings.  It can be used to see if two 
c-strings have the same prefix of some length.

Now, strncmp indeed seems to be packaged up in core.stdc.string, 
but i would like to use some something like it on 2 d strings 
(which, as i understand it, need not be zero-terminated).

I suppose it would be possible to do some conversion with 
toStringz() or something and then invoke the strncmp(), but that 
seems very wordy and also it's not clear that it would handle all 
pairs of d strings (e.g., what if there were some 0's in the 
first count characters?).

So i would like to call a d function which works on d strings, 
but don't want to write my own if one already exists.  (At the 
very least, i'd have to get a much sharper understanding of d 
strings, whether internal 0's can occur, etc.  And i would not 
want to do egregious string allocation.)

TIA for any info!