Adjusting to MacOS Ventura and gcc12: plotit software changes

 Sportsfans,

The upgrade to MacOS Ventura has broken my Fortran programming environment, mainly by moving the directories of the operating system around so that older versions of gfortran and gcc cannot find their proper libraries.  Rather than spend hours recreating the original file structures and libraries from old backups and the Relocated Items folders, I decided to level up to the latest GNU C and Fortran compilers as maintained by MacPorts.  These are gcc12 -- version 12 of the venerable GNU freeware package.  The old Fortran programmers must have retired, because these new compilers have discarded several aspects of Fortran 66 syntax that I learned as a teenager.  I don't write code with this older syntax, having transitioned to the Fortran 77 syntax of do/end do loops and if/then/else branches while in graduate school.  Nevertheless, there is plenty of legacy code in my toolboxes, and some of these subroutines have do loops that end on an executable statement, and others contain nested loops that terminate on the same numbered statements.  The new Fortran boffins outlawed these syntaxes, along with the arithmetic IF statement, in Fortran 2018.  My legacy codes have plenty of arithmetic IF statements, so all of these had to be reprogrammed to comply with gcc12.

This post is the first of a handful of posts that will provide these upgraded codes.  The first is the venerable, and oft-hated, plotit subroutine for on-the-fly XY-plotting within a Fortran program.  I include versions of plotit.f 

gfortran -c plotit.f  -L/usr/X11/lib -I/usr/X11/include -lX11

gcc -c xlplotit.c -L/usr/X11/lib -I/usr/X11/include -lX11

ar r plotlib.a plotit.o xlplotit.o

ranlib plotlib.a

gfortran -o PROGRAM PROGRAM.f plotlib.a -L/usr/X11/lib -I/usr/X11/include -lX11

I keep the compiled plotit object code in a signature directory for adding to my codes:

 /Users/jjpark/Plotxy/plotlib.a

In the zipfile Plotlib_fort18.zip I include updated versions of contour.f and makedat.f for similar on-the-fly plotting of a contour plot, and test-plotting with plotit.  I haven't tested these, so shoot me an email if they crash.

https://drive.google.com/drive/folders/0B5cfVtTS8QXZTGc1WnViSE5RWjA?resourcekey=0-YidcAd0wJGPRR1PhAyUYNA&usp=sharing