Thread Subject: combining structure array

Hi,
Can some one let me know how I can combine 2 structure arrays. For example,

tmp1 = struct; tmp2= struct;
tmp1.aa1 = 3;
tmp1.aa2 = -5;
tmp2.bb1 = 2;
tmp2.bb2 = 6;

I would like to combine tmp1 and tmp2 into tmp3 such that tmp3 has all the fields in tmp1 and tmp2, so tmp3 contains aa1, aa2, bb1 and bb2 fields.

In my application, I will have to combine many times the structure arrays.
Thanks a lot in advance.
Pete

I found a function "CATSTRUCT" by Jos; very useful!

http://www.mathworks.com/matlabcentral/fileexchange/7842