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

[Arjen Markus <arjen.markus895@gmail.com>]

Do you know why the strings command does not show the identification
string,
which clearly present in the executable file, even though it should examine
the
entire file (the --all option does not alter the output)?

Regards,

Arjen

Op vr 3 jun. 2022 om 07:22 schreef Janne Blomqvist <
blomqvist.janne@gmail.com>:

> On Thu, Jun 2, 2022 at 10:33 PM Kay Diederichs
> <kay.diederichs@uni-konstanz.de> wrote:
> > Am 02.06.22 um 21:06 schrieb Janne Blomqvist:
> > > As an alternative approach, make a command-line option (say, "-v")
> > > that prints the version number of the program, name of the author and
> > > other pertinent information, as well as the output of
> > > compiler_version() and compiler_options(), and then exits. That would
> > > ensure that those calls won't be optimized away.
> > >
> >
> > I was thinking of such a -v option as well, and it is a solution for
> > some situations, but not e.g. for a dynamically loadable library (see
> > https://cims.nyu.edu/~donev/Fortran/DLL/DLL.Forum.txt ) which is my
> > situation (
> > https://strucbio.biologie.uni-konstanz.de/xdswiki/index.php/LIB ). I'd
> > like to be able to see later which compiler version and options were
> > used when compiling that library, because over the years of distributing
> > this code, compilers and options have been changing.
>
> For the library case, can't you make a function
> libraryname_print_version_info() or whatever you want to call it that
> does the same? Of course, if the user never calls that function, uses
> a static library, and everything is compiled with -ffunction-sections
> and linked with --gc-sections that will not work, but otherwise the
> string should still be there in the binary so you should be able to
> find it with the strings tool?
>
> > -g includes the source code, which is not always desired, and is not
> > possible here due to license issues - there was no concept of "open
> > source" as we have it today in the 80ies when this code was started.
>
> Hmm, maybe that's the case, I don't have a legal opinion to offer on
> this, sorry.
>
> > Also I think it makes the code slower.
>
> No, at least with GCC -g doesn't affect the code generation. It makes
> the binary bigger so it takes longer to copy around, and depending on
> how the debug info is spread out in the binary some of that might be
> unnecessarily mapped into memory when running, but I think you'd be
> very hard pressed to measure any difference in performance.
>
> --
> Janne Blomqvist
>