I want to write a C function that concatenates a list of
 strings whose lengths are unknown at compile-time.  How can I
 do this efficiently?

 Date: 30-Oct-91
 X-Contributor: Brian Marasca <71230.1650@compuserve.com>

 If you're concerned about performance, the best possible solution
 would be to define a maximum string length beforehand.  If you can
 do that, this piece of code, submitted by Brian Marasca
 (71230,1650 on Compuserve), is pretty high-performance:

    #define MAXLEN 120   /* Set this to the maximum required length. */

    CLIPPER cStrCat()
    {
        char *p, *q, *buf ;
        int cx = 1, parms = _parinfo ( 0 ) ;

        q = buf = _xgrab (MAXLEN + 1) ;

        while (parms--)
        {
             p = _parc (cx++) ;
             while (*p) *q++ = *p++ ;
        }
        *q = '\0' ;       /* very important! */

        _retc (buf) ;
        _xfree (buf) ;
    }