how to check if global optimal solution was obtained

[convex_optimization]

I am using the following for cplex solver:

   ops=sdpsettings('solver',Solver, 'savesolveroutput',2, 'verbose',0, 'debug',1, 'cplex.solutiontarget',3);

'cplex.solutiontarget',3  is used to force towards global optimal solution.
After solution is obtained, how do we check whether  global optimal was achieved?

[Johan Löfberg]

It is just as hard to check if a solution is globally optimal, as actually solving the problem

Your only option is thus to look at the various diagnostics supplied by cplex (termination strings etc)