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1/*2 * Copyright © 2018 Alexey Dobriyan <adobriyan@gmail.com>3 *4 * Permission to use, copy, modify, and distribute this software for any5 * purpose with or without fee is hereby granted, provided that the above6 * copyright notice and this permission notice appear in all copies.7 *8 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES9 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF10 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR11 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES12 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN13 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF14 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.15 */16#include <sys/types.h>17#include <sys/stat.h>18#include <fcntl.h>19#include <errno.h>20#include <unistd.h>21 22int main(void)23{24 char buf[64];25 int fd;26 27 fd = open("/proc/self/wchan", O_RDONLY);28 if (fd == -1) {29 if (errno == ENOENT)30 return 4;31 return 1;32 }33 34 buf[0] = '\0';35 if (read(fd, buf, sizeof(buf)) != 1)36 return 1;37 if (buf[0] != '0')38 return 1;39 return 0;40}41