max_path_bytes

The maximum length of a file path that the operating system will accept.

Paths, including those returned from file system operations, may be longer than this length, but such paths cannot be successfully passed back in other file system operations. However, all path components returned by file system operations are assumed to fit into a u8 array of this length.

The byte count includes room for a null sentinel byte.

On Windows, []u8 file paths are encoded as WTF-8.
On WASI, []u8 file paths are encoded as valid UTF-8.
On other platforms, []u8 file paths are opaque sequences of bytes with no particular encoding.

Source

Implementation

pub const max_path_bytes = switch (native_os) {
    .linux, .macos, .ios, .freebsd, .openbsd, .netbsd, .dragonfly, .haiku, .solaris, .illumos, .plan9, .emscripten, .wasi, .serenity => posix.PATH_MAX,
    // Each WTF-16LE code unit may be expanded to 3 WTF-8 bytes.
    // If it would require 4 WTF-8 bytes, then there would be a surrogate
    // pair in the WTF-16LE, and we (over)account 3 bytes for it that way.
    // +1 for the null byte at the end, which can be encoded in 1 byte.
    .windows => windows.PATH_MAX_WIDE * 3 + 1,
    else => if (@hasDecl(root, "os") and @hasDecl(root.os, "PATH_MAX"))
        root.os.PATH_MAX
    else
        @compileError("PATH_MAX not implemented for " ++ @tagName(native_os)),
}