sync() on a read-only file handle doesn't work on cygwin either

Cygwin fsync() is implemented in terms of the Win32 FlushFileBuffers()
API which requires GENERIC_WRITE access.

1 files changed, 4 insertions, 1 deletions

diff --git a/dist/IO/t/io_xs.t b/dist/IO/t/io_xs.t
index 85fbc5668f..b73144794f 100644
--- a/dist/IO/t/io_xs.t
+++ b/dist/IO/t/io_xs.t
@@ -45,7 +45,10 @@ SKIP:
        or skip "No fsync", 1;
     $^O eq 'aix'
       and skip "fsync() documented to fail on non-writable handles on AIX", 1;
+    $^O eq 'cygwin'
+      and skip "fsync() on cygwin uses FlushFileBuffers which requires a writable handle", 1;
     open my $fh, "<", "t/io_xs.t"
        or skip "Cannot open t/io_xs.t read-only: $!", 1;
-    ok($fh->sync, "sync to a read only handle");
+    ok($fh->sync, "sync to a read only handle")
+	or diag "sync(): ", $!;
 }