A simple app to get run times from a thread

Just a quick app to test and demonstrate how to get run times from a
specific thread on FreeBSD.

procstat_cpu_time.hpp

@@ -0,0 +1,34 @@
+/*
+ * SPDX-FileCopyrightText: 2025 Eilertsens Kodeknekkeri
+ * SPDX-FileCopyrightText: 2025 The FreeBSD Foundation
+ * SPDX-FileContributor: Harald Eilertsen <haraldei@anduin.net>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#ifndef __PROCSTAT_CPU_TIME_HPP
+#define __PROCSTAT_CPU_TIME_HPP
+
+#include <pthread.h>
+
+/**
+ * Helper function to get the kernel thread id from a pthread_t handle.
+ */
+long ktid_from_pthread(pthread_t thread);
+
+/**
+ * Get the user and system runtime for a given thread by using libprocstat.
+ *
+ * Possibly slower than the fast_cpu_time method, as we have to iterate over the
+ * thread info (kinfo_proc) structs for every thread in the process until we find
+ * the correct one.
+ *
+ * Also the returned struct is dynamically allocated by the procstat_getprocs function,
+ * and has to be freed by procstat_freeprocs after it's no longer needed.
+ *
+ * While this may be ok when retreiving the info for one struct, it would be way more
+ * efficient to check multiple threads at once using the same returned array of structs.
+ */
+void procstat_cpu_time(pthread_t thread, struct timeval * utime, struct timeval * stime);
+
+#endif