Source/ThirdParty/libsysprof-capture/sysprof-clock.c

/* sysprof-clock.c
 *
 * Copyright 2016-2019 Christian Hergert <chergert@redhat.com>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are
 * met:
 *
 * 1. Redistributions of source code must retain the above copyright notice,
 *    this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * Subject to the terms and conditions of this license, each copyright holder
 * and contributor hereby grants to those receiving rights under this license
 * a perpetual, worldwide, non-exclusive, no-charge, royalty-free,
 * irrevocable (except for failure to satisfy the conditions of this license)
 * patent license to make, have made, use, offer to sell, sell, import, and
 * otherwise transfer this software, where such license applies only to those
 * patent claims, already acquired or hereafter acquired, licensable by such
 * copyright holder or contributor that are necessarily infringed by:
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 * (a) their Contribution(s) (the licensed copyrights of copyright holders
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 *     Contribution.
 *
 * Except as expressly stated above, no rights or licenses from any copyright
 * holder or contributor is granted under this license, whether expressly, by
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 * DISCLAIMER
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 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
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 */

#include "config.h"

#include <assert.h>
#include <stdbool.h>

#include "sysprof-clock.h"
#include "sysprof-macros-internal.h"

int sysprof_clock = -1;

void
sysprof_clock_init (void)
{
  static const int clock_ids[] = {
#ifdef __APPLE__
    _CLOCK_MONOTONIC,
#else
    CLOCK_MONOTONIC,
#endif
#ifdef __linux__
    CLOCK_MONOTONIC_RAW,
    CLOCK_MONOTONIC_COARSE,
    CLOCK_REALTIME_COARSE,
#endif
    CLOCK_REALTIME,
  };

  if (sysprof_clock != -1)
    return;

  for (unsigned int i = 0; i < SYSPROF_N_ELEMENTS (clock_ids); i++)
    {
      struct timespec ts;
      int clock_id = clock_ids [i];

      if (0 == clock_gettime (clock_id, &ts))
        {
          sysprof_clock = clock_id;
          return;
        }
    }

  sysprof_assert_not_reached ();
}