include/lttng/ust-clock.h

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