Variadic Functions in Co-array Fortran

Here’s a function that will take an arbitrary number of int values as arguments.

program variadic_functions
  implicit none
  integer :: total, i
  integer, dimension(:), allocatable :: nums

  call sum([1, 2])
  call sum([1, 2, 3])

  allocate(nums(4))
  nums = [1, 2, 3, 4]
  call sum(nums)
  
contains

  subroutine sum(nums)
    integer, dimension(:), intent(in) :: nums
    integer :: i, total

    print *, nums
    total = 0
    do i = 1, size(nums)
      total = total + nums(i)
    end do
    print *, total
  end subroutine sum

end program variadic_functions

To compile and run this program, save the code in a file named variadic_functions.f90 and use a Fortran compiler.

$ gfortran -o variadic_functions variadic_functions.f90
$ ./variadic_functions
 1 2
  3
 1 2 3
  6
 1 2 3 4
  10

Now that we can run and build basic Fortran programs, let’s learn more about the language.

Multiple Return Values in Co-array Fortran

Closures in Co-array Fortran

Learn X By Example

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Variadic Functions in Co-array Fortran