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/*
* Copyright (C) 2011 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// Minimal test program for clock
#include <pthread.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>
// this thread soaks the CPU so that clock() function will advance
void *cpu_hog(void *arg)
{
for (;;) {
// the system call should not be optimized away by the compiler
(void) getpid();
}
}
int main(int argc, char **argv)
{
pthread_t thread;
clock_t ticks10, ticks15;
// do not call clock() here so we can test initialization
// soak the CPU for 10 seconds, then read clock
pthread_create(&thread, NULL, cpu_hog, NULL);
sleep(10);
ticks10 = clock();
// soak the CPU for 5 more seconds, then read clock
sleep(5);
ticks15 = clock();
// print the results
printf("CLOCKS_PER_SEC = %ld ticks/sec\n", (clock_t) CLOCKS_PER_SEC);
printf("At 10 secs clock=%lu, at 15 secs clock=%lu\n", ticks10, ticks15);
// exit could wait for the other thread to complete
_exit(EXIT_SUCCESS);
}
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