include/lttng/ust-clock.h

   1 /*
   2  * SPDX-License-Identifier: LGPL-2.1-only
   3  *
   4  * Copyright (C) 2014  Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   5  */
   6
   7 #ifndef LTTNG_UST_CLOCK_H
   8 #define LTTNG_UST_CLOCK_H
   9
  10 #include <stdint.h>
  11 #include <stddef.h>
  12
  13 #ifdef __cplusplus
  14 extern "C" {
  15 #endif
  16
  17 /*
  18  * Set each callback for the trace clock override, and then enable the
  19  * override. Those functions return negative error values on error, 0 on
  20  * success.
  21  */
  22
  23 typedef uint64_t (*lttng_ust_clock_read64_function)(void);
  24 typedef uint64_t (*lttng_ust_clock_freq_function)(void);
  25 typedef int (*lttng_ust_clock_uuid_function)(char *uuid);
  26 typedef const char *(*lttng_ust_clock_name_function)(void);
  27 typedef const char *(*lttng_ust_clock_description_function)(void);
  28
  29 /*
  30  * Set/Get clock override read callback. This callback should return the
  31  * current clock time (a 64-bit monotonic counter).
  32  */
  33 int lttng_ust_trace_clock_set_read64_cb(lttng_ust_clock_read64_function read64_cb);
  34 int lttng_ust_trace_clock_get_read64_cb(lttng_ust_clock_read64_function *read64_cb);
  35
  36 /*
  37  * Set/Get clock override frequency callback. This callback should return
  38  * the frequency of the clock in cycles per second.
  39  */
  40 int lttng_ust_trace_clock_set_freq_cb(lttng_ust_clock_freq_function freq_cb);
  41 int lttng_ust_trace_clock_get_freq_cb(lttng_ust_clock_freq_function *freq_cb);
  42
  43 /*
  44  * Set/Get clock override unique identifier.
  45  * LTTNG_UST_UUID_STR_LEN is the maximum length of uuid string. Includes
  46  * final \0.
  47  */
  48 #define LTTNG_UST_UUID_STR_LEN         37
  49
  50 int lttng_ust_trace_clock_set_uuid_cb(lttng_ust_clock_uuid_function uuid_cb);
  51 int lttng_ust_trace_clock_get_uuid_cb(lttng_ust_clock_uuid_function *uuid_cb);
  52
  53 /*
  54  * Set/Get clock override name.
  55  */
  56 int lttng_ust_trace_clock_set_name_cb(lttng_ust_clock_name_function name_cb);
  57 int lttng_ust_trace_clock_get_name_cb(lttng_ust_clock_name_function *name_cb);
  58
  59 /*
  60  * Set/Get clock override description.
  61  */
  62 int lttng_ust_trace_clock_set_description_cb(lttng_ust_clock_description_function description_cb);
  63 int lttng_ust_trace_clock_get_description_cb(lttng_ust_clock_description_function *description_cb);
  64
  65 /*
  66  * Use the clock override rather than the default clock.
  67  */
  68 int lttng_ust_enable_trace_clock_override(void);
  69
  70 #ifdef __cplusplus
  71 }
  72 #endif
  73
  74 #endif /* LTTNG_UST_CLOCK_H */