c_char is i8 for all apple targets

[gnzlbg]

AFAICT this should be u8 for the aarch64 and arm iOS, watchOS, etc. targets.

[highjeans]

https://developer.apple.com/documentation/swift/cchar
Seems like its differs between apple platforms, I will take a look into this.

[chengr4]

I am uncertain if my check was correct.

According to bsd/arm/limits.h,

#define CHAR_MAX        127             /* max value for a char */
#define CHAR_MIN        (-128)          /* min value for a char */

char in Apple ARM platform should also be i8. and Rust libc defines c_char at src/primitives.rs:

pub use core::ffi::{
    c_char
}

$\Rightarrow$

The core lib gives the right judgement I guess.

all(
            not(windows),
            not(target_vendor = "apple"),
            not(target_os = "vita"),
            any(
                target_arch = "aarch64",
                target_arch = "arm",
                target_arch = "csky",
                target_arch = "hexagon",
                target_arch = "msp430",
                target_arch = "powerpc",
                target_arch = "powerpc64",
                target_arch = "riscv32",
                target_arch = "riscv64",
                target_arch = "s390x",
                target_arch = "xtensa",
            )
        ) => {
            pub(super) type c_char = u8;
        }
        // On every other target, c_char is signed.
        _ => {
            pub(super) type c_char = i8;
        }

[tgross35]

288706a switched to the exports from core so this shouldn't be a problem anymore. Thank you for pointing this out!