rustc: argument must be a string literal

Question

I have test.rs:

const TEST: &'static str = "Test.bin";

fn main() {
    let x = include_bytes!(TEST);
}

rustc test.rs

How to fix this error?

error: argument must be a string literal

 --> test.rs:4:22
  |
4 |     let x = include_bytes!(TEST);
  |                      ^^^^

How to fix ? The answer is in the question: put a string literal between the parenthesis. `let x = include_bytes!("test.bin");` — Denys Séguret, Oct 05 '21 at 12:31
I need to take this value out of the function to make interaction with the code easier — , Oct 05 '21 at 12:32
Then you can't use this macro. Do you really expect to include in the binary something dynamic ? — Denys Séguret, Oct 05 '21 at 12:32
Wait let me get this right, this macro can't even accept a STATIC string parameter? What kind of useless bs is this then? I mean, it is very bad practice to hardcode filenames inside functions, so who thought this would be a good idea? — Spectraljump, Mar 14 '22 at 19:20

score 4 · Accepted Answer · answered Oct 05 '21 at 12:33

The macro expects a string literal, so it cannot be a variable:

include_bytes!("Test.bin");

Alternatively you could create a macro that will expand into the desired value too:

macro_rules! test_bin {
    // `()` indicates that the macro takes no argument.
    () => {
        "Test.bin"
    };
}

fn main() {
    let x = include_bytes!(test_bin!());
}

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rustc: argument must be a string literal

1 Answers1