binary is used to constrain a variable to be binary.
F = binary(x)
Setting up a binary linear program can be done as
x = binvar(n,1); optimize(A*x<b,c'*x)
x = sdpvar(n,1); optimize([A*x<=b, binary(x)],c'*x)
The binary constraint is imposed on the involved variables, not the actual expression. Hence, the following two constraints are equivalent
F = binary(x); F = binary(pi+sqrt(2)*x);
If possible, use binvar instead as there are some parts in YALMIP where it can exploit integrality on an earlier stage if the varaibles have been defined as such.