1 Topic by JohnWasilewski (edited by JohnWasilewski 2020-09-28 12:59:22)

Topic: Compile one source file

I'm a bit rusty with SF, so please can anyone tell me, is there a way to compile just one source file, without causing SF to try to build a project?

My immediate purpose is to compile dislin.f90, to make sure the .mod file was compiled using the same version of GFortran as SF uses.  I can do it manually, from the CLI, but why bother to look up the syntax and fiddle about with CLI commands to get into the right directory etc when I  can use SF?

I can envisage a slight possibility that it might prove occasionally useful, with a whole stack of source files added to a project, to try compiling just one file.  One could explore any warnings and errors the compiler might provide, in case it finds anything that SF doesn't.  (To Jeff: will SF always find the same errors as GFortran finds, or might GFortran find some more?).
---
John

  • jeff
  • Administrator
  • Offline

Re: Compile one source file

John,

Simply Fortran does not allow compiling a single file to an object file.  While I can see the utility in this operation, there is just far too much confusion surrounding the term "compile" with users.  I think a significant portion of users, quite possibly a majority, will assume the term "compile" means that an executable will result in the operation.  Perhaps an obscured menu option like "Generate Object File" would make sense.

If you want to generate a .mod file from dislin.f90, the command line would simply be:

gfortran -c -o dislin.o dislin.f90

If Simply Fortran installed cleanly, gfortran should be on your path (on Windows and GNU/Linux).  That command should result in dislin.o and dislin.mod.  However, you'll probably need to include dislin.o in future projects, which you were already doing with dislin.f90 anyway.

The whole reason we don't provide a better DISLIN package that would include a prebuilt module is that the DISLIN license is quite vague about distributing their software as a commercial entity.  Basically, it disallows any commercial entity to distribute DISLIN without a commercial license.  While it might not be meant to limit our use case (providing the library to developers pre-configured for our compiler), it effectively does so in legalese.  So the SF Package Manager only provides a script to download DISLIN and save some of its files in reasonable locations.

Errors displayed in Simply Fortran are generated by the compiler itself.  Simply Fortran will occasionally attempt to compile the contents of an editor with the same flags as the project (though more warnings are enabled), and it will then highlight the problems in the editor.  So yes, the errors in Simply Fortran are the errors the compiler finds.

Jeff Armstrong
Approximatrix, LLC

3 Reply by JohnWasilewski (edited by JohnWasilewski 2020-09-28 13:09:07)

Re: Compile one source file

Thanks for your interesting reply Jeff.  It hadn't occurred to me that many users might not be aware of the separate stages of compiling object files and then linking these, plus libraries, to produce an executable.  I now see why SF's emphasis is on a single 'build' operation, which does indeed make it much simpler for users.  In the way that we used to compile each file separately (or with a string of commands in a script), and keep slogging away intil the last of the object files is finally ready, I see that is exactly what SF also does, by ignoring source files that are already compiled at every new build attempt, and when they're all done, moving on to the linking stage.  To users, all it needs is just one mouse click on 'Build'.  Oh how much less effort than it used to take!  That was when I learned to write some pretty cool script files that gave me a kind of project-specific IDE in a DOS screen.  Well, actually, it was a CP/M screen on an Apple ][ Plus.

And we never even bother with overlays any more - or I don't think so. 
As a matter of curiosity only, do you know whether  there any overlay linkers still around?  Does anyone remember the fabulous 'PLINK'?  It could overlay code on code, code over data, data over code etc., all into a single executable, that read chunks of itself into memory at a time and kept re-reading each time it needed the next part.  Made it possible to link an executable for an 80-element 8-noded isoparametric quadrilateral plate bending and plane strain FE analysis program (by Hinton and Owen) in a 48k microcomputer with a 120k external floppy disk.

I have found where the Simply Fortran files are squirrelled away in MacOS and, rather than installing an independent copy of GFortran, F951, GCC etc (because MacOS can't see where these already are), I've slipped in an extra line in my $HOME/.zprofile file (as MacOS 10.15 uses zsh not bash), to add the Smply Fortran pathname to $PATH, which now lets me use GFortran from the CLI.  This is better because it avoids needless duplication and makes it easier for me to re-compile dislin.f90 whenever SF updates contain new versions of GFortran.  I don't think there's any harm in doing it this way because I am not touching any files or directories any higher than $HOME.

I think the 64-bit version I need to be using of dislin.f90 is the one in ../dislin/gf/real64.
Is that right?

Thank you for giving me the syntax to compile the dislin.mod file.  Having finally done that correctly, I am now able at long last to remove dislin.f90 from my project outline and leave SF to find and search through the .mod file, the path to which I have added to Options>File locations.  I'm not yet clear why or when dislin.o will be needed.  I see it's a binary file containing nothing but zeros and the words '--text' and '--TEXT'. Anyway, if SF's 'build' operation asks for it, I'll supply it.

On the subject of the commercial licence, did you spot the message from Helmut Michels a few months ago that he had now retired from Max Planck Institut and was now releasing dislin for private and commercial use?  I can try to find a copy if you don't recall seeing it.  I assume this means that the restriction you mention is now lifted, although perhaps there are still some passages you are mindful of in the licence terms that mean it's not completely lifted.
---
John