#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/select.h>
#include <unistd.h>


int
main(int argc, const char* const* argv)
{
        const char* config[] = {
                argc >= 2 ? argv[1] : "rwe",
                argc >= 3 ? argv[2] : "rwe",
                argc >= 4 ? argv[3] : "rwe"
        };

        fd_set readSet;
        fd_set writeSet;
        fd_set errorSet;

        FD_ZERO(&readSet);
        FD_ZERO(&writeSet);
        FD_ZERO(&errorSet);

        for (int fd = 0; fd < 3; fd++) {
                if (strchr(config[fd], 'r'))
                        FD_SET(fd, &readSet);
                if (strchr(config[fd], 'w'))
                        FD_SET(fd, &writeSet);
                if (strchr(config[fd], 'e'))
                        FD_SET(fd, &errorSet);
        }

        int result = select(3, &readSet, &writeSet, &errorSet, NULL);
        fprintf(stderr, "select(): %d\n", result);

        for (int fd = 0; fd < 3; fd++) {
                fprintf(stderr, "fd %d: %s%s%s\n", fd,
                        FD_ISSET(fd, &readSet) ? "r" : " ",
                        FD_ISSET(fd, &writeSet) ? "w" : " ",
                        FD_ISSET(fd, &errorSet) ? "e" : " ");
        }

        return 0;
}