Salut Dominique, moin Richard, hello all, (Answering Richard's question from PR33330.) Dominique Dhumieres wrote: >> Btw, is it mandated by the fortran standard to pass a scalar as array >> reference? >> > Does anyone knows the answer? or should it be asked on comp.lang.fortran? >
The standard mandates that (when the dummy argument has no VALUE attribute) variables are passed as reference; I'm pretty sure that the rest is implementation dependent. I think the question arose form: character :: my_char which is a scalar character variable which takes exactly one character. However, the following is also a scalar variable: character(len=10) :: my_char which contains 10 characters. It has the same storage size as an array with ten elements with one character each: character(len=1), dimension(10) :: my_char As a scalar character variable with len > 1 needs an array reference, it is quite natural to pass also a scalar variable with length 1 as array reference. I think the standard also allows to pass it as non-array reference, which happens (for obvious reasons) if one uses C Bindings. (In this case the standard mandates len=1; for strings one has thus to use an array.) Hmm, thinking it over, I think on can say that the standard mandates that an array reference is passed. Let's assume two functions, expecting, respectively, character(len=1) :: arg character(len=*) :: arg (len=* allows for any lengths; the length is passed as an additional argument in both cases.) In the main program I do now: call mySubroutine( 'a' ) in order to decide whether one needs to pass an array reference or not, one needs to know whether len=1 or len=*. This is only possible if one knows the explicit interface (= function definition); but Fortran allows also implicit interfaces (i.e. "assume mySubroutine exists, it returns VOID and takes 0 to oo arguments of a certain but unknown type"). Tobias
