> $glob2 = glob(".c"); # returns the second match of "" and stores it in $glob2

Not true.

    $ touch 1 2 3 4.c 5.c 6.c 7 8
    $ ls
    1  2  3  4.c  5.c  6.c  7  8
    $ perl -E '
         @globvals = glob("*");
         say "globvals = @globvals";
         $glob1 = glob("*");
         $glob2 = glob("*.c");
         say "glob1 = $glob1\nglob2 = $glob2"
      '
    globvals = 1 2 3 4.c 5.c 6.c 7 8
    glob1 = 1
    glob2 = 4.c

As you can see, the third call to glob returns the expected value.

Here's how glob is documented in the perlfunc document[1].

    glob    In list context, returns a (possibly empty) list of filename
            expansions on the value of EXPR such as the standard Unix shell
            /bin/csh would do. In scalar context, glob iterates through such
            filename expansions, returning undef when the list is exhausted.

[1]: http://perldoc.perl.org/functions/glob.html