Re: [RFC] Add code to support evaluating Fortran exponentiation expression

[Wu Zhou <woodzltc@cn.ibm.com>]

On Mon, 20 Jun 2005, Eli Zaretskii wrote:

> By all means, please add anything you think might be of use to GDB
> users who debug Fortran programs.

Eli,

It might be desirable to add the following text:

GDB support Fortran language, but mainly support output from the GNU Fortran
compiler(maybe more specifically GNU F77 compiler here?). It also has the
following limitation:

1. You need to use "break MAIN__" to make the Fortran program to stop at the
begining of the execution. To set breakpoint at a subroutine or function 
named "sub", you need to add a trailing underscore, to say "break sub_".

2. GDB can't handle the evaluation of exponentiation expression yet.

3. Current GDB can't handle the evaluation of substring expression. 
(There are some code intended to handle this, but it doesn't work with 
g77-3.2.3, g77-3.3.3 and g77-3.4.3.  I will code a testcase to show this
later.  Not sure how to fix this yet.)

4. GDB can't handle the evaluation of Fortran intrinsic functions, such as 
"mod", "abs" and so on.

5. GDB can't handle some Fortran-90 or Fortran-95 extension, such as the 
self-defined data type, such as the array addition operation, array 
substraction operation...

Maybe there are still others.  There isn't much compilable Fortran 
testcases in current testsuite.  So it is hard to say what works and what 
not.  

BTW, I am thinking of doing something to enhance GDB's support of Fortran 
language (not only f77, but also f95 or some other fortran compiler). Do 
you have any suggestion on this?  Thanks!

Cheers
- Wu Zhou