Re: is there a way to find out gfortran version and/or options from a given binary?

[Kay Diederichs <kay.diederichs@uni-konstanz.de>]

On 6/3/22 10:16, Janne Blomqvist via Fortran wrote:
> On Fri, Jun 3, 2022 at 10:30 AM Arjen Markus via Fortran
> <fortran@gcc.gnu.org> wrote:
>>
>> Hi Kay,
>>
>> (you forgot to reply to everybody ;))
>>
>> I am using a Windows version of gfortran and strings. I use a file viewer
>> that comes with the Total Commander file manager. So, it may be something
>> specific to that version of strings.
> 
> One caveat being that Fortran strings are not NULL terminated like C
> strings. So a tool that searches for C-style strings in a binary might
> not find Fortran-style strings unless there happens to be a NULL after
> them for some other reason. The version of strings included in GNU
> binutils searches for strings terminated by any non-printable
> character, so it finds Fortran style strings (and a lot of noise which
> isn't strings).
> 
>> Op vr 3 jun. 2022 om 09:25 schreef Kay Diederichs <
>> kay.diederichs@uni-konstanz.de>:
>>> @Janne thanks for pointing out that -g does not make the code slower.
>>> Is there an option that prevents the sourcecode to be included when -g is
>>> used?
> 
> You might try -frecord-gcc-switches. There's also
> -grecord-gcc-switches (which puts the info somewhere in the debug
> data), which is enabled by -g, but without -g it seems it doesn't do
> anything.
> 

thanks for pointing at -frecord-gcc-switches . This appears to be what I was looking for.
Googling for frecord-gcc-switches (without the leading "-", of course) brings up very interesting exchanges.
For the record, when -frecord-gcc-switches  is used in compilation,
objdump -s --section=.GCC.command.line <binary>
or
readelf -p .GCC.command.line <binary>
shows the compiler options.
I have not (yet) tried to find out how -grecord-gcc-switches differs, nor if and why the suggestion to
"Introduce a new GCC option, --record-gcc-command-line" was rejected
( https://gcc.gnu.org/legacy-ml/gcc-patches/2019-11/msg00434.html ).

Thanks to all who responded!
Kay