I went into this thinking: C is basically cleaned up FORTRAN, right? I know C? This should be easy, right? Right off the bat I find there will be a lot of difficulties entirely not of the kind I'm used to in programming. After a brief adventure with accidentally naming my file .f and not .f90 causing horrific and baffling errors, I run a hello world off the Internet. There's a space before the printout. Hm, how do I turn that off?

https://stackoverflow.com/a/31236043

Oh my fuck, *what*?

I get frustrated with C all the time for being fundamentally a 70s language. It may be I'm about to learn the pain of using a *50s language*.

(Alternately, I hear modern FORTRAN has all kinds of fancy niceties like operator overloading and might not resemble traditional FORTRAN all that much. But then I have the problem if I pick up a random tutorial it's hard to guess which *decade's* standard it's teaching me from, or if it's the GNU extension, if the GNU extension is that different, etc.)

Just learned FORTRAN has an aint() function

Don't that just beat all

Here is my current program. At the moment, all it does is take a command line argument (a path) and attempt to open the specified file. I build it with `gfortran src/puzzle.f90 -std=f2023 -o program`

https://github.com/mcclure/aoc2024/blob/822e460f81b944c21ca675303b868c45b22a4c2b/04-01-wordsearch/src/puzzle.f90

I'm having two problems, one serious, one unserious.

The unserious problem: I want to abort if the # of arguments is bad. If I do "error stop", it prints a backtrace, which I didn't ask for. If I do "call abort", gfortran fails to link ("undefined reference to 'abort_').

Here's my serious FORTRAN problem (code link in previous post):

The recommended GET_COMMAND_ARGUMENT function seems to assume you know the length of the argument ahead of time. Obviously, I don't.

https://gcc.gnu.org/onlinedocs/gfortran/GET_005fCOMMAND_005fARGUMENT.html

It allows me to pass in an `allocatable` string, but I believe it is leaving that string of length 0 if I do not ALLOCATE() it, and the fetched string is ''. Is there a way to get the length of a command-line argument before GET-ing it?

I see GET_COMMAND, but that's… awkward

…hm. I am concerned.

According to the FORTRAN working group

https://wg5-fortran.org/N2201-N2250/N2212.pdf

As of the 2023 standard, an un-allocated deferred-length variable may have its length set by calling intrinsic procedures; they give GET_COMMAND as an example specifically, and StackOverflow users assert GET_COMMAND_ARGUMENT is also included.

I don't get this behavior. My argument is being input as ''.

Do you think this means my code (linked above) is wrong, or that gfortran -std=f2023 is nonconformant?

@mcc how do you mean ". ? the shell won't let you enter it.
You'd have to quote it as '".' Using the example proggy from the manual for GET_COMMAND_ARGUMENT gives you then

$ ./a.out 333 '".'
./a.out
333
".