V: Linux being misidentified as macOS

[elimisteve]

When running

$ ./vc -o v .

on Linux, I get the error:

cc: error: unrecognized command line option ‘-mmacosx-version-min=10.7’

In main.v I see

        if c.os == MAC {
                a << '-mmacosx-version-min=10.7'
        }

which indicates that my Linux machine is being misidentified as macOS.

(It also assumes that I'm compiling with clang but that's another issue.)

EDIT: the solution is to run

$ ./vc -os linux -o v .

to compile on Linux... which solves OS "detection" -- thank you to @superwhiskers for figuring this out! :+1: -- but I personally can't compile on Linux yet.

[superwhiskers]

ok so here's what i've deduced so far, @elimisteve
c.os is deduced using the a set of compile-time if expressions
here's the code that does that

    mut _os := MAC
    // No OS specifed? Use current system
    if target_os == '' {
        $if linux {
            _os = LINUX
        }
        $if mac {
            _os = MAC
        }
        $if windows {
            _os = WINDOWS
        }
    }
    else {
        switch target_os {
        case 'linux': _os = LINUX
        case 'windows': _os = WINDOWS
        case 'mac': _os = MAC
        }
    }

i'm still working on deducing what conditions are used to figure out the operating system. i'll update you if i find anything out

[elimisteve]

@superwhiskers Thanks :+1: . I've reached similar conclusions and can say that even compiling with clang does not help with the OS misindentification:

$ clang -std=c11 v.c -w -o vc && ./vc -o v .
cc: error: unrecognized command line option ‘-mmacosx-version-min=10.7’
V panic: clang error

[superwhiskers]

yeah. clang wouldn't have anything to do with it though. it's probably some funky os detection stuff

[elimisteve]

I wouldn't be surprised if different compilers used different criteria to determine the OS they are running on at compile time, but I don't know how clang does it versus gcc; maybe they're the same.

[superwhiskers]

ah ok. so it relies on the c compiler to do the os checking.
l2517-2530

        name := p.check_name()
        if name in SupportedPlatforms {
            if not {
                p.genln('#ifndef $name')
            }
            else {
                p.genln('#ifdef $name')
            }
            p.check(LCBR)
            p.statements_no_curly_end()
            if ! (p.tok == DOLLAR && p.peek() == ELSE) {
                p.genln('#endif')
            }
        }

so basically, your c compiler thinks you're on macos, or your c compiler doesn't think you're on macos, windows or linux and so it falls back to the default, macos

[superwhiskers]

i'm not quite sure how you could fix this, but what exactly are you running

[superwhiskers]

there's one quick hack you could do though which involves passing -os linux to the compiler which will override the os checking part

[elimisteve]

there's one quick hack you could do though which involves passing -os linux to the compiler which will override the os checking part

Any idea how to do that? Literally adding -os linux to clang or gcc doesn't work for me.

I see https://stackoverflow.com/a/8249232 ... Maybe <= that is how the OS detection logic should be implemented in the first place?

[superwhiskers]

to the v compiler, not the c compiler

[elimisteve]

Ah. Well I get:

$ ./vc -os linux -o v .
cc: error: x86_64-linux-gnu: No such file or directory
cc: error: unrecognized command line option ‘-target’
V panic: clang error

[elimisteve]

You're right though -- that fixed OS "detection"! :tada: Thank you; well done.

[superwhiskers]

you can now manually compile the v binary by running
```
clang -o v ~/.vlang*/compiler.c
````
(i think)

[superwhiskers]

ah ok. np

[elimisteve]

        // Cross compiling linux
        sysroot := '/Users/alex/tmp/lld/linuxroot/'

Jeez, more terrible hardcoding...

[superwhiskers]

oh yeah. there's a lot more than just that though :)

[superwhiskers]

i've been working on fixing some of that but i decided to take a break to work on some of the issues in the issue tracker

[spytheman]

On Linux, you can also compile v.c with:
gcc -Dlinux -g -std=c11 -w -o vc v.c

[lutherwenxu]

Should be fixed now by 0.1.0 . It now depends on C macros instead of random defines in the code.