unable to replicate a syscall from c (single line) | Zig Programming Language | Page 1

i trying to make syscall open on current directory, i dont understand why it behave differently some one can help me ? 🙂
they both correctly compile with no error

const std = @import("std");

pub fn syscall2(number: usize, arg1: usize, arg2: usize) usize {
    return asm volatile ("syscall"
        : [ret] "={rax}" (-> usize),
        : [number] "{rax}" (number),
          [arg1] "{rdi}" (arg1),
          [arg2] "{rsi}" (arg2),
        : "rcx", "r11", "memory"
    );
}

const O_DIRECTORY = 65536; 

pub fn main() void {
    const s = ".";
    const r : usize = syscall2(2, @ptrToInt(&s),  O_DIRECTORY);
    std.debug.print("{}\n", .{@bitCast(i64, r)});           // -2
    std.debug.print("{}\n", .{std.os.linux.getErrno(r)});   // os.linux.errno.generic.E.NOENT
    return;
}

c code

#include <unistd.h>
#include <stdio.h>

#define O_DIRECTORY 65536
int main()
{
    int a = syscall(2, ".", 0 | O_DIRECTORY);
    printf("%d", a);               // 3
}

#unable to replicate a syscall from c (single line)