Fortran Understanding Common Blocks in Fortran 77

  • Thread starter Thread starter *FaerieLight*
  • Start date Start date
  • Tags Tags
    Blocks Fortran
Click For Summary
In Fortran 77, a common block, such as "common /hmat/ a,b,c,d", allows multiple variables (a, b, c, d) to share the same memory space identified by the name "hmat". The common block does not require prior definition of "hmat"; it can be introduced directly in the common block statement. To access the variables stored in "hmat", one typically uses the same common block declaration in any program unit that needs to access those variables. This facilitates data sharing across different program units without the need for explicit passing of variables. For further guidance, a tutorial link on named common blocks is provided for additional context.
*FaerieLight*
Messages
43
Reaction score
0
Hi

I'm having some trouble with understanding the whole concept of the common block in Fortran 77.

Here is an example:

common /hmat/ a,b,c,d

It means that all the variables a,b,c,d are all contained in hmat. But does hmat need to be defined previously for the above example to make sense? Or can the first time you refer to it be in a common block code, as above? And if all the variables are stored in hmat, how do I open hmat to see them?

Thanks
 
Technology news on Phys.org

Thread 'For those who ask: "What programming language should I learn?"'

Learn If you want to write code for Python Machine learning, AI Statistics/data analysis Scientific research Web application servers Some microcontrollers JavaScript/Node JS/TypeScript Web sites Web application servers C# Games (Unity) Consumer applications (Windows) Business applications C++ Games (Unreal Engine) Operating systems, device drivers Microcontrollers/embedded systems Consumer applications (Linux) Some more tips: Do not learn C++ (or any other dialect of C) as a...
View full post »

Similar threads

Fortran An advanced example in fortran 77
  • · Replies 22 ·
Replies
22
Views
4K
Fortran How does Fortran know the Inputs and Outputs of Subroutines
  • · Replies 59 ·
2
Replies
59
Views
11K
Fortran Fortran 77 variable declaration issue
  • · Replies 3 ·
Replies
3
Views
2K
Fortran Porting fortran program-problem with padding in common
  • · Replies 8 ·
Replies
8
Views
6K
Fortran Fortran Code Help for Mechanical Engineers | Solving Debugging Issues
  • · Replies 17 ·
Replies
17
Views
4K
My Website For Creating Interactive Visuals Linked To Equations
  • · Replies 4 ·
Replies
4
Views
3K
Fortran What are the Differences Between Fortran 77 and Fortran 90?
  • · Replies 1 ·
Replies
1
Views
3K
Fortran Fortran error: Big array size, solution?
  • · Replies 3 ·
Replies
3
Views
8K
Fortran Help with Debugging Fortran Code | Plato Compiler
  • · Replies 4 ·
Replies
4
Views
3K
Caching: Actual role of byte offset field in the cache address?
  • · Replies 2 ·
Replies
2
Views
2K