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typesfortran

Allocating a variable's type based on another variable's type in a subroutine

Let's say I have a variable foo which is of class(BaseType). Type1 and Type2 are types that extends BaseType, and I am trying to allocate foo to be the same type as a second variable, bar, which has previously been declared as either Type1 or Type2.

When I try to write a subroutine using the function TYPE to do this, I get a compilation error:

SUBROUTINE TESTING(foo,bar)
CLASS(BaseType), INTENT(INOUT) :: foo 
CLASS(BaseType), INTENT(IN) :: bar
ALLOCATE(TYPE(bar)::foo)
END SUBROUTINE TESTING

The compilation error is:

Error: Allocate-object at (1) is neither a data pointer nor an allocatable variable

Is there a way to do what I am describing? Or is there an error with my implementation? This subroutine is written in a module if that is relevant. Thanks in advance.

Solution

  • The specifier mold= is exactly for this but you also have to fix what the error message is complaining about. foo is neither allocatable nor pointer and it must be one of these to appear in allocate. After fixing that, you can do

    allocate(bar, mold=foo)