src/tests/system/kernel/select_check.cpp

   1 #include <errno.h>
   2 #include <stdio.h>
   3 #include <stdlib.h>
   4 #include <string.h>
   5 #include <sys/select.h>
   6 #include <unistd.h>
   7
   8
   9 int
  10 main(int argc, const char* const* argv)
  11 {
  12         const char* config[] = {
  13                 argc >= 2 ? argv[1] : "rwe",
  14                 argc >= 3 ? argv[2] : "rwe",
  15                 argc >= 4 ? argv[3] : "rwe"
  16         };
  17
  18         fd_set readSet;
  19         fd_set writeSet;
  20         fd_set errorSet;
  21
  22         FD_ZERO(&readSet);
  23         FD_ZERO(&writeSet);
  24         FD_ZERO(&errorSet);
  25
  26         for (int fd = 0; fd < 3; fd++) {
  27                 if (strchr(config[fd], 'r'))
  28                         FD_SET(fd, &readSet);
  29                 if (strchr(config[fd], 'w'))
  30                         FD_SET(fd, &writeSet);
  31                 if (strchr(config[fd], 'e'))
  32                         FD_SET(fd, &errorSet);
  33         }
  34
  35         int result = select(3, &readSet, &writeSet, &errorSet, NULL);
  36         fprintf(stderr, "select(): %d\n", result);
  37
  38         for (int fd = 0; fd < 3; fd++) {
  39                 fprintf(stderr, "fd %d: %s%s%s\n", fd,
  40                         FD_ISSET(fd, &readSet) ? "r" : " ",
  41                         FD_ISSET(fd, &writeSet) ? "w" : " ",
  42                         FD_ISSET(fd, &errorSet) ? "e" : " ");
  43         }
  44
  45         return 0;
  46 }