vscode with fortran and makefiles on macos (Big Sur) - visual-studio-code

Question

I am a new user to vscode. I viewed Lukas Lamm's video of vscode Fortran, but I am still having problems:
can't build code
can't launch code for debug
I have a makefile which requires some environment variable definitions for, say, the compiler type, $COMPILER. I have included the makefile extension but when I do a 'make all' there, the environment variables remain undefined. I have no problem doing a 'make all' in the vscode terminal window. How do I configure the Makefile extension to parse these environment variables?
I did write a launch.json file to run my code - I think exactly the way Luke Lamm indicated in his video. My code requires an input file:
heatx.exe < heatx.inp
but it never finds it - it just hangs at the read statement (It finds heatx.exe fine). Below is my launch.json script:
{
"version": "0.2.0",
"configurations": [
{
"name": "Run GDB",
"type": "cppdbg",
"request": "launch",
"program": "${workspaceRoot}/heatx.exe",
"args": [
"<",
"${workspaceFolder}/heatx.inp"
],
"stopAtEntry": false,
"cwd": "${workspaceRoot}",
"externalConsole": false,
"MIMode": "lldb",
"preLaunchTask": "make"
}
]
}
I checked other vscode questions about input files and this was exactly the solution they suggested.

Answer 1

I don't think this has anything to do with makefiles so you should probably remove the makefile tag.
I'm no expert at vscode, but I don't think this can work:
"program": "${workspaceRoot}/heatx.exe",
"args": [
"<",
"${workspaceFolder}/heatx.inp"
],
IO redirection (handling of <) is a feature of the shell. Here you're not invoking a shell, you're invoking heatx.exe, so there's nothing to handle the redirection. This basically runs your program heatx.exe with two arguments: a literal < and the file .../heatx.inp. But your program is reading from stdin, and nothing is there.
You either need to rework your program so it takes a filename and opens that file and reads from it, so you can run heatx.exe heatx.inp, then you can use:
"program": "${workspaceRoot}/heatx.exe",
"args": [
"${workspaceFolder}/heatx.inp"
],
Or you have to run a shell and tell it to run your program in a shell script, like this:
"program": "/bin/sh",
"args": [
"-c",
"${workspaceRoot}/heatx.exe < ${workspaceFolder}/heatx.inp"
],
Note! This will work on any POSIX system like Linux or MacOS. You don't say what system you're working on but this likely won't work on Windows unless you have various things installed and set up, and you might need to use a different path for a shell. Or I guess you could try to write it with cmd.exe but all this Windows stuff is beyond me.