winmm/tests: Pass the full size of MIDIHDR to midiOutPrepareHeader().

[Huw Davies]

Signed-off-by: Huw Davies <huw at codeweavers.com>
---
 dlls/winmm/tests/midi.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/dlls/winmm/tests/midi.c b/dlls/winmm/tests/midi.c
index b80d5d2..f3ea62c 100644
--- a/dlls/winmm/tests/midi.c
+++ b/dlls/winmm/tests/midi.c
@@ -514,8 +514,8 @@ static void test_midiStream(UINT udev, HWND hwnd)
 
         rc = midiOutPrepareHeader((HMIDIOUT)hm, &mhdr, offsetof(MIDIHDR,dwOffset)-1);
         ok(rc==MMSYSERR_INVALPARAM, "midiOutPrepare tiny rc=%s\n", mmsys_error(rc));
-        rc = midiOutPrepareHeader((HMIDIOUT)hm, &mhdr, offsetof(MIDIHDR,dwOffset));
-        ok(!rc, "midiOutPrepare old size rc=%s\n", mmsys_error(rc));
+        rc = midiOutPrepareHeader((HMIDIOUT)hm, &mhdr, sizeof(mhdr));
+        ok(!rc, "midiOutPrepare size rc=%s\n", mmsys_error(rc));
         ok(mhdr.dwFlags & MHDR_PREPARED, "MHDR.dwFlags when prepared %x\n", mhdr.dwFlags);
 
         /* The device is still in paused mode and should queue the message. */
@@ -557,9 +557,9 @@ static void test_midiStream(UINT udev, HWND hwnd)
         /* Native fills dwOffset regardless of the cbMidiHdr size argument to midiStreamOut */
         ok(1234567890!=mhdr.dwOffset, "play left MIDIHDR.dwOffset at %u\n", mhdr.dwOffset);
 
-        rc = midiOutUnprepareHeader((HMIDIOUT)hm, &mhdr, offsetof(MIDIHDR,dwOffset));
+        rc = midiOutUnprepareHeader((HMIDIOUT)hm, &mhdr, sizeof(mhdr));
         ok(!rc, "midiOutUnprepare rc=%s\n", mmsys_error(rc));
-        rc = midiOutUnprepareHeader((HMIDIOUT)hm, &mhdr, offsetof(MIDIHDR,dwOffset));
+        rc = midiOutUnprepareHeader((HMIDIOUT)hm, &mhdr, sizeof(mhdr));
         ok(!rc, "midiOutUnprepare #2 rc=%s\n", mmsys_error(rc));
 
         trace("MIDIHDR stream flags=%x when finished\n", mhdr.dwFlags);
@@ -584,9 +584,9 @@ static void test_midiStream(UINT udev, HWND hwnd)
 
         mhdr.dwFlags |= MHDR_ISSTRM;
         /* Preset flags (e.g. MHDR_ISSTRM) do not disturb. */
-        rc = midiOutPrepareHeader((HMIDIOUT)hm, &mhdr, offsetof(MIDIHDR,dwOffset));
+        rc = midiOutPrepareHeader((HMIDIOUT)hm, &mhdr, sizeof(mhdr));
         ok(!rc, "midiOutPrepare used flags %x rc=%s\n", mhdr.dwFlags, mmsys_error(rc));
-        rc = midiOutUnprepareHeader((HMIDIOUT)hm, &mhdr, offsetof(MIDIHDR,dwOffset));
+        rc = midiOutUnprepareHeader((HMIDIOUT)hm, &mhdr, sizeof(mhdr));
         ok(!rc, "midiOutUnprepare used flags %x rc=%s\n", mhdr.dwFlags, mmsys_error(rc));
 
         rc = midiStreamRestart(hm);
-- 
2.8.2