i have call c function fortran, want in vectorised loop. working intel 16.0.3 compilers on linux. so options are: can try , function inline or can use simd function (i want use openmp simd this, want portable , use openmp). if call fortran fortran works both ways. passing arguments use linear/ref clause pass reference vector of values rather vector of references , seems work efficiently. in c linear/ref clause not recognised. i can function nominally vectorise inserting gathers , scatters , performance no better scalar (at least small test function). if put linear(ref(r,s)) in fortran interface block message the uval or ref modifiers must not used on dummy argument value attribute. i can performance using trick of passing value fortran , returning value function return. produces vectorised function, , performance good, unfortunately real function needs return more 1 value. if try inline c function, won't work. opt-report tells me callsite cannot inlined. tr...