1 /*
2  * PROJECT:         ReactOS API tests
3  * LICENSE:         GPL - See COPYING in the top level directory
4  * PURPOSE:         Test for NtQueryTimerResolution and NtSetTimerResolution.
5  * PROGRAMMER:      Aleksandar Andrejevic <theflash AT sdf DOT lonestar DOT org>
6  */
7 
8 #include "precomp.h"
9 
10 START_TEST(TimerResolution)
11 {
12     NTSTATUS Status;
13     ULONG CurrentResolution;
14     ULONG MinimumResolution;
15     ULONG MaximumResolution;
16     ULONG CurrentResolution2;
17 
18     /* Get the current timer resolution */
19     Status = NtSetTimerResolution(0,        /* Ignored */
20                                   FALSE,    /* Don't change resolution */
21                                   &CurrentResolution);
22 
23     /*
24      * If the timer resolution hasn't been changed for this process,
25      * it returns STATUS_TIMER_RESOLUTION_NOT_SET
26      */
27     ok_hex(Status, STATUS_TIMER_RESOLUTION_NOT_SET);
28 
29     /*
30      * Get the timer resolution limits and current timer resolution
31      * using a different method
32      */
33     Status = NtQueryTimerResolution(&MinimumResolution,
34                                     &MaximumResolution,
35                                     &CurrentResolution2);
36 
37     /* This function should always return STATUS_SUCCESS */
38     ok_hex(Status, STATUS_SUCCESS);
39 
40     /* The MinimumResolution should be higher than the MaximumResolution */
41     ok(MinimumResolution >= MaximumResolution, "MaximumResolution higher than MinimumResolution!\n");
42 
43     /* These two values should be the same */
44     ok_hex(CurrentResolution, CurrentResolution2);
45 
46     /*
47      * Even if you give it invalid values,
48      * NtSetTimerResolution will return STATUS_SUCCESS,
49      * but it will not change the resolution.
50      */
51     Status = NtSetTimerResolution(MinimumResolution + 1,
52                                   TRUE,
53                                   &CurrentResolution);
54     ok_hex(Status, STATUS_SUCCESS);
55     printf("Current resolution: %lu ; minimum resolution: %lu\n", CurrentResolution, MinimumResolution);
56     ok(CurrentResolution <= MinimumResolution, "Current resolution: %lu became too high! (minimum resolution: %lu)\n", CurrentResolution, MinimumResolution);
57 
58     Status = NtSetTimerResolution(MaximumResolution - 1,
59                                   TRUE,
60                                   &CurrentResolution);
61     ok_hex(Status, STATUS_SUCCESS);
62     printf("Current resolution: %lu ; maximum resolution: %lu\n", CurrentResolution, MaximumResolution);
63 #if 0 // Why? This doesn't hold true on Windows Server 2003.
64     ok(abs((LONG)MaximumResolution - (LONG)CurrentResolution) < 200, "Current resolution: %lu became too low! (maximum resolution: %lu)\n", CurrentResolution, MaximumResolution);
65 #endif
66 
67     /* Get the current timer resolution */
68     Status = NtSetTimerResolution(0,        /* Ignored */
69                                   FALSE,    /* Don't change resolution */
70                                   &CurrentResolution);
71 
72     /* Since we have changed the resolution earlier, it returns STATUS_SUCCESS. */
73     ok_hex(Status, STATUS_SUCCESS);
74 
75     /* Get the current timer resolution again */
76     Status = NtSetTimerResolution(0,        /* Ignored */
77                                   FALSE,    /* Don't change resolution */
78                                   &CurrentResolution);
79 
80     /* The resolution is not changed now, so it should return STATUS_TIMER_RESOLUTION_NOT_SET */
81     ok_hex(Status, STATUS_TIMER_RESOLUTION_NOT_SET);
82 }
83