何时在声明函数时使用EXTERNAL

最新推荐文章于 2025-02-10 00:48:45 发布

转载最新推荐文章于 2025-02-10 00:48:45 发布 · 4.4k 阅读

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本文详细介绍了在编程中使用EXTERNAL声明的情况，包括如何通过EXTERNAL声明避免名称冲突，以及在传递子程序名称时确保编译器正确解析的方法。

EXTERNAL is needed in a variety of situations:

- If you pass a subroutine name to a subroutine and there is no explicit interface (as was the case in FORTRAN 77), EXTERNAL makes it clear to the compiler a subroutine is meant.

- If you use a subroutine name with the same name as an intrinsic subroutine (Note that compilers can add intrinsics of their own, so potentially any subroutine that you write yourself could be in confict with the compiler or the next version of the compiler, unless you use EXTERNAL consistently).

EXTERNAL is not needed when there can be no confusion over the meaning of the name - a module procedure or a name appearing in an interface block.