proc-uptime-001.c (1299B)
1/* 2 * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com> 3 * 4 * Permission to use, copy, modify, and distribute this software for any 5 * purpose with or without fee is hereby granted, provided that the above 6 * copyright notice and this permission notice appear in all copies. 7 * 8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES 9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF 10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR 11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES 12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN 13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. 15 */ 16// Test that values in /proc/uptime increment monotonically. 17#undef NDEBUG 18#include <assert.h> 19#include <stdint.h> 20#include <sys/types.h> 21#include <sys/stat.h> 22#include <fcntl.h> 23 24#include "proc-uptime.h" 25 26int main(void) 27{ 28 uint64_t start, u0, u1, i0, i1; 29 int fd; 30 31 fd = open("/proc/uptime", O_RDONLY); 32 assert(fd >= 0); 33 34 proc_uptime(fd, &u0, &i0); 35 start = u0; 36 do { 37 proc_uptime(fd, &u1, &i1); 38 assert(u1 >= u0); 39 assert(i1 >= i0); 40 u0 = u1; 41 i0 = i1; 42 } while (u1 - start < 100); 43 44 return 0; 45}