File stat in zig 0.16-dev

Help
, ,
1

how do I get the uid and gid of a file? I’ve searched through the official documentation but still don’t quite understand how to do it.

std.Io.File + stat: No uid/gid?
2

You have to drop to platform specific APIs, Io doesn’t provide it because that information isn’t available on all supported platforms.

I think?? it might change in the future

Since std.posix has been nuked, you have to go even lower to std.os.your_os_here.

Assuming you’re on linux:

const linux = std.os.linux;

var statx: linux.Statx = undefined;
// there is a `BASIC_STATS` decl which includes uid, gid and other common stats
const errno = linux.errno(linux.statx(io_file.handle, "", linux.AT.EMPTY_PATH, .{ .GID = true, .UID = true }, &statx));
switch (errno) {
    .SUCCESS => {},
    .ACCES => {},
    .BADF => {},
    .FAULT => {},
    .INVAL => {},
    .LOOP => {},
    .NAMETOOLONG => {},
    .NOENT => {},
    .NOMEM => {},
    .NOTDIR => {},
    // no other errors are possible
    else => unreachable,
}
// only these are filled due to the mask passed
const uid, const gid = .{ statx.uid, statx.gid };
4 Likes
3

My guess is that you’ll need to go through std.os.linux.statx() (e.g. Zig Documentation which populates a StatX struct: Zig Documentation, and this has uid and gid).

It’s probably not part of the generic std.Io interface because uid and gid are not portable.

3 Likes
4

In case you need to get and set, there is nowstd.Io.File.Permissions. You have setPermissions() function as well.

5

Hi, @vulpesx @floooh .

I used std.os.linux.statx and it solved the problem; I can now correctly retrieve the required data on Linux.

On macOS, I use std.c.fstat.

Thank~