It is call action(mySubX) provided action looks as subroutine action(sub) !either – not recommmended, it is old FORTRAN77 style external sub !or – recommended interface subroutine sub(aA, aB) integer,intent(…) :: aA, aB end subroutine end interface ! NOT BOTH!! call sub(argA, argB) provided action knows what to put there as argA, argB to represent aA, … Read more
It is a function with a prototype that takes two scalar arguments. There are strong arguments for not actually using Perl prototypes in general – as noted in the comments below. The strongest argument is probably: Far More Than Everything You’ve Ever Wanted to Know about Prototypes in Perl There’s a discussion on StackOverflow from … Read more
To answer your question: Yes Fortran does preserve the value of internal variables through function and subroutine calls. Under certain conditions … If you declare an internal variable with the SAVE attribute it’s value is saved from one call to the next. This is, of course, useful in some cases. However, your question is a … Read more
Yes, Fortran has procedure pointers, so you can in effect alias a function name. Here is a code example which assigns to the function pointer “f_ptr” one function or the other. Thereafter the program can use “f_ptr” and the selected function will be invoked. module ExampleFuncs implicit none contains function f1 (x) real :: f1 … Read more
Modules are always the right thing to use 😉 If you have a very simple F90 program you can include functions and subroutines in the ‘contains’ block: program simple implicit none integer :: x, y x = … y = myfunc(x) contains function myfunc(x) result(y) implicit none integer, intent(in) :: x integer :: y … … Read more
I’m a frequent abuser of &, but mostly because I’m doing weird interface stuff. If you don’t need one of these situations, don’t use the &. Most of these are just to access a subroutine definition, not call a subroutine. It’s all in perlsub. Taking a reference to a named subroutine. This is probably the … Read more