用gfortran强制显式变量声明 [英] Force explicit variable declaration with gfortran

问题描述

我使用mex连接matlab中的一些Fortran代码（f90），偶尔会有matlab冻结。

过去，由于不匹配，我发生冻结之间的数据类型（如整数* 4与整数* 8）。

我链接的代码有许多隐式定义的变量，所以我想知道是否有隐藏的数据类型冲突只能偶尔出现。为了排除数据类型不匹配的原因，我希望编译器要求显式声明所有变量。

问题：

1. 如何获得gfortran要求全部变量在编译时显式声明？否则，有什么办法可以至少得到警告？




2. 是否所有体系结构中的gfortran都将真实数据类型解释为特定类型？如果是这样，哪一个是它（真实* 4，真实* 8，...）？
   

3. 是否有强迫gfortran解释真实数据类型是一种特定的类型，比如说real * 4？




4. 关于什么让fortran代码在从mex编译的例程中调用时冻结在MATLAB中（数据类型不匹配除外）？
   
   
   

   感谢您的帮助。
   
   

   在我弄清楚之前，我会经历许多代码行，试图列出所有隐式定义的变量。
   不用说，我会非常感谢任何人把我从这样无聊的任务中解救出来......
   
   

   Best，
   
   

   G
   

   解决方案

   
   
   1. 声明为通过添加隐式无。
   
   
   2. 我相信默认的真实数据类型是 real * 4 。
   
   
   3. 您可以使用命令行标记 -fdefault-real-8 来强制所有变量声明为真实被解释为 real * 8
   
   

   注意（为了编写更多的代码，不一定要解决当前的错误）：
   如果您使用的是Fortran 90代码，则可以使用 real （kind = 4）或 real（kind = 8） with gfortran而不是 real * 4 或 real * 8 语法。我已经不再使用命令行标志设置实数或整数大小，而是使用整数，参数:: REAL_SIZE 变量来保存适当的数字（我通常会去对于4或8，因为我使用的所有编译器都支持它们，但是如果你想变得非常便携，你应该使用 selected_real_kind 例程）
   

   I am linking some fortran code (f90) from matlab using mex and I am having matlab freeze occasionally.

   In the past, I had freezing happening due to mismatch between data types (say integer*4 vs integer*8).

   The code I am linking has many implicitly defined variables, so I am wondering if there is a hidden data type conflict that only occurs occasionally.

   To rule out data type mismatch as the cause of the freeze, I would like to have the compiler requiring all variables to be explicitly declared.

   Questions:

   1. How do I get gfortran to require all variables to be explicitly declared at compile time? Failing that, is there any way to at least get warnings?

   2. Is a "real" data type interpreted by gfortran as a specific kind in all architectures? If so, which one is it (real*4, real*8, ...)?

   3. Is there anyway to force gfortran to interpret the "real" data type as a specific kind, say "real*4"?

   4. Any ideas on what makes the fortran code to freeze when called from a mex compiled routine in matlab (other than data type mismatches)?

   Thanks for any help.

   Until I figure this out I will be going through many lines of codes trying to list all implicitly defined variables. Needless to say, I will be tremendously grateful to anyone who frees me from such a boring task...

   Best,

   G.

   解决方案

   1. You can require all variables to be explicitly declared by adding implicit none.
   2. I believe the default "real" data type is a real*4.
   3. You can use a command-line flag -fdefault-real-8 to force all variables declared as real to be interpreted as a real*8

   Note (for writing more code, not necessarily trying to solve the current bug): If you're using Fortran 90 code, you can use real(kind=4) or real(kind=8) with gfortran rather than the real*4 or real*8 syntaxes. I've moved away from setting the real or integer size using command-line flags and instead use an integer, parameter :: REAL_SIZE variable to hold the appropriate number (I typically go for 4 or 8 because all the compilers I use support them, but if you want to be very portable you should use the selected_real_kind routine)

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