Bitshift operator expected int, found bool during including C header

[craggy tangle]

Hello, I'm trying to @cInclude('fenster.h') but when I compile, the zig compiler throws an error on the translated source code for:

f->mod = (!!(m & ControlMask)) | !!(m & ShiftMask) << 1) | (!!(m & Mod1Mask) << 2) | (!!(m & Mod4Mask) << 3);

It doesn't seem to like the C trick of double negation to get numbers. As it gives "Bitshifting operator expected int, but found bool" for that line. In the translated zig, I can see a few casts, do my first thought was export the header to zig and add another cast, but it does #define os-specific headers that I don't really want to translate to cImports by hand

[shrewd aurora]

Does it error without using the macro, or only when you use the macro?

[craggy tangle]

Which macro? @cInclude?

[shrewd aurora]

I mean are you trying to call the function that has an error, or are you trying to call another function and it's erroring anyway

[craggy tangle]

It errors on build even when I don't call the function

[shrewd aurora]

I'd report it to the issue tracker - ideally if translate-c fails to translate something, it should set just the one declaration to @compileError().

to work around it, you might be able to define a c macro with @cDefine() to get it to skip that function

[craggy tangle]

It's a pretty important function to the library though... Darn, alright

[shrewd aurora]

oh if you need it then don't do that

usually single-header libraries will require you to define a macro to include the implementation so you can build it separately than including it. but it doesn't look like fenster does that

[craggy tangle]

I did see some old zig builds that had that define at the top, but when I added it, the linker complained about un-found functions

here's the exact error

import.zig:2783:100: error: bit shifting operation expected integer type, found 'bool'
                        f.*.mod = ((@intFromBool(!!((m & (@as(c_int, 1) << @intCast(2))) != 0)) | (!!((m & (@as(c_int, 1) << @intCast(0))) != 0) << @intCast(1))) | (!!((m & (@as(c_int, 1) << @intCast(3))) != 0) << @intCast(2))) | (!!((m & (@as(c_int, 1) << @intCast(6))) != 0) << @intCast(3));

      f->mod = (!!(m & ControlMask)) | (!!(m & ShiftMask) << 1) |
               (!!(m & Mod1Mask) << 2) | (!!(m & Mod4Mask) << 3);

is the line in the headerfile that is the problematic one

[shrewd aurora]

I think in zig it might be best to build fenster.h with addCSourceFile() in build.zig, and then manually create bindings for it in zig

either that or edit fenster.h to put every function body behind an ifdef guard

[craggy tangle]

and I'm assuming that this is because the bishift outputs a number, the exclamation marks convert that to a bool, then it tries to do an integer compare and fails on types?

hmm, that's not right

It's translating

(!!(m & Mod1Mask) << 2)

to

(!!((m & (@as(c_int, 1) << @intCast(3))) != 0) << @intCast(2)))

I guess it doesn't really matter though, it's not working

[shrewd aurora]

what it's doing is true << 1 and it needs to see that it's going to be shifted and do like @as(c_int, @intFromBool(true)) << @intCast(1) or something

[craggy tangle]

alright... Thanks for the direction!

all this to construct an enum of bits

[shrewd aurora]

here's a smaller reproduction if you want to open an issue for zig

int shift(int a) {
    return !a << 1;
}

[craggy tangle]

alright, thank you!