Re: Reference to derived type element by index?

"Rob Crain" <r.a.crain@xxxxxxxxxxxx> wrote in message
news:fsokhs$kda$1@xxxxxxxxxxxxxxxxxxxxxx

Since it's not mission critical and I'm pushed for time I opted for an
inelegant select case statement; it does the job. Thanks to all for your
responses though - when I get time to tune the code I'll revisit ***'s
suggestion, it looks like it might be the answer.

Since C binding was introduced, you can point at any TARGET with
any kind of pointer you want, just like in C.

C:\gfortran\clf\fake_label>type fake_label.f90
module fake_label_mod
implicit none
private
integer, parameter :: circle_label_len = 20
public circle_datatype
type circle_datatype
real radius
real x
real y
real z
character(len=circle_label_len) circle_label
end type circle_datatype
end module fake_label_mod

program fake_label
use fake_label_mod
use ISO_C_BINDING
implicit none
type(circle_datatype), target :: circle1
real, pointer :: pcircle1(:)
integer i

call C_F_POINTER(C_LOC(circle1), pcircle1, [4])
pcircle1 = [(i,i=3,15,4)]
circle1%circle_label = "It's a circle"
write(*,*) circle1
end program fake_label

C:\gfortran\clf\fake_label>c:\gfortran\win64\bin\x86_64-pc-mingw32-gfortran
fake
_label.f90 -ofake_label

C:\gfortran\clf\fake_label>fake_label
3.0000000 7.0000000 11.000000 15.000000 It's a
circle


Thus in the above I have pointed at the four REAL elements of circle1
with a pointer to an array of REALs, and accessed them as an array
of REALs.

--
write(*,*) transfer((/17.392111325966148d0,6.5794487871554595D-85, &
6.0134700243160014d-154/),(/'x'/)); end


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