CreateSymbolicLink on windows 10

Question

ever since they were first introduced, creating a symbolic link required a full administrator. Running from a normal or from a non-elevated process CreateSymbolicLink would fail.

In windows 10, CreateSymbolicLink fails as well in these circumstances, that is it doesn't create anything, however it returns a success code (!) and GetLastError is 0 too. So there's no way to detect the error other than checking if the symlink file exists

Looks like a bug in windows 10?

Answer 1

Have experienced the same. But: The success code you seem to get is an error code. So it seems the have changed the return type of CreateSymbolicLink from BOOLEAN to int

Answer 2

This workarround works for me:
Change the return value into an integer.

1 = success
for all other values call GetLastWin32Error

[DllImport("kernel32.dll", EntryPoint = "CreateSymbolicLinkW", CharSet = CharSet.Unicode, SetLastError = true)]
static extern int CreateSymbolicLink(string lpSymlinkFileName, string lpTargetFileName, SYMBOLIC_LINK_FLAG dwFlags);

public static int CreateSymbolicLinkFix(string lpSymlinkFileName, string lpTargetFileName, int dwFlags) {
    var result = CreateSymbolicLink(lpSymlinkFileName, lpTargetFileName, dwFlags);
    if (result == 1) return 0; // Success
    return Marshal.GetLastWin32Error();
}