Fortran OOP循环依赖处理，接口 [英] Fortran OOP circular dependency handling, interfaces
问题描述
Compiler：ifort version 12.1.5
Compiler: ifort version 12.1.5
我正在写一些Fortran代码，我想使用一些F2003的OOP功能，击中一些绊脚石。省略示例，我希望有两个派生类型A和B，每个派生类型都有一个指向另一个实例的指针。在Fortran中，模块之间的循环依赖性被明确禁止，因此这两种类型必须驻留在同一个模块中。它编译：
I'm writing some Fortran code and I'd like to make use of some F2003 OOP features, but I'm hitting some stumbling blocks. Paring down the example, I wish to have two derived types A and B, each of which have a pointer to instances of the other. In Fortran, circular dependencies between modules are explicitly disallowed, so these two types would have to reside in the same module. This compiles:
module testModule
implicit none
type A
type(B),pointer :: b1
end type A
type B
type(A),pointer :: a1
end type B
contains
[some possibly type-bound procedures]
end module
现在，我想为这些类型实现一些构造函数，并尝试以下代码：
Now, I want to implement some constructors for these types, and try this code:
module testModule
implicit none
type A
type(B),pointer :: b1
end type A
interface A
module procedure A_ctor
end interface
type B
type(A),pointer :: a1
end type B
interface B
module procedure B_ctor
end interface
contains
function A_ctor()
type(A),target :: A_ctor
end function
function B_ctor()
type(B),target :: B_ctor
end function
end module
$ b b
现在，这不会编译，引发错误
Now, this doesn't compile, throwing an error
这不是派生类型名称。 [B]
This is not a derived type name. [B]
。为什么添加接口会抛出错误？如何在Fortran中处理导出类型的循环依赖，因为在C ++中会使用转发类声明？
on line 5 above. Why does adding the interfaces throw an error? How does one handle circular dependencies in derived types in Fortran, as one would use a forward class declaration in C++?
推荐答案
是正确的Fortran 2003.你正在以正确的方式处理循环类型依赖。编译器是错误的。
Your code is correct Fortran 2003. You are handling the circular type dependency in the correct way. The compiler is in error.
我经历过，并看到其他人报告问题与ifort 12.1.5和程序员覆盖的结构构造函数（其中有一个函数的通用接口具有派生类型结果，接口与派生类型具有相同的名称，就像你在这里一样）。这种情况的一种解决方法是将构造函数的通用接口（及后续引用）重命名为与派生类型不同的名称。
I have experienced and seen others report issues with ifort 12.1.5 and programmer overrides of structure constructors (where there is a generic interface to a function that has a derived type result, with the interface having the same name as the derived type - as you have here). A workaround for this situation to rename the generic interface (and subsequent references) for the constructor function to a name different from the derived type.
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