How to call procedure from function. Getting error Invalid use of side-effecting or time-dependent operator in 'INSERT EXEC' within a function.

Hi!I am trying to call procedure from function but getting following error.Invalid use of side-effecting or time-dependent operator in 'INSERT EXEC' within a function.Actually I want table valued function so that I can use it in outer apply to process every left input.and in that function I am calling another already available procedure. may be this is not valid here but another alternative I can see is use of cursor which I have to prevent because of possible slowness of query.Can anybody suggest some workaround?