Fortran可变范围的困难 [英] Difficulty with fortran variable scope

问题描述

我已经在fortran的一个函数中初始化了一个变量。我在另一个功能中使用它。但价值并不一样。在其他函数调用中，我正在获取垃圾值。

例如：

 
条目a（ ）
 num_calls = 0 
 
条目b（）
 num_calls = num_calls + 1 
 

从条目b中，我得到了num_calls作为一些垃圾

解决方案在经典Fortran（Fortran 77或更早版本）中， d确保num_calls被定义在一个公共块中 - 可能是一个已命名的公共块。

  COMMON / magic / num_calls 
  

我没有使用过Fortran 90，所以我不知道它有什么额外的功能。它可能会保留为了向后兼容而命名的公共块，但也可能提供更好的一些。

我也欺骗了，并且使用了变量的隐式声明。完整的，我应该写：

  INTEGER * 4 num_calls 
 COMMON / magic / num_calls 
 
 code> 




I have intialized one variable in one of the fortran functions. I am using it in another function. But the value is not remains same. In other function call I am getting garbage value. How do i maintain the initialized value.

Ex:

entry a()
num_calls=0

entry b()
num_calls= num_calls + 1

From entry "b" i am getting num_calls as some garbage

解决方案

In classic Fortran (Fortran 77 or earlier), you'd ensure that num_calls is defined in a common block - probably a named common block.

COMMON /magic/ num_calls

I've not used Fortran 90, so I don't know what extra facilities it has. It likely retains named common blocks for backwards compatibility, but likely provides something better too.

I cheated, too, and used an implicit declaration of the variable. In full, I should write:

INTEGER*4 num_calls
COMMON /magic/ num_calls

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