SELECT_TUT(2)                 System Calls Manual                SELECT_TUT(2)

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       select, pselect - <?><?><?><?><?><?><?><?><?><?><?><?><?>
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LIBRARY
       Standard C library (libc, -lc)

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       <?><?><?><?><?><?><?><?> select(2)

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       The select()  and pselect()  system calls are used to efficiently
       monitor multiple file descriptors, to see if any of them is, or
       becomes, "ready"; that is, to see whether I/O becomes possible, or an
       "exceptional condition" has occurred on any of the file descriptors.

       This page provides background and tutorial information on the use of
       these system calls.  For details of the arguments and semantics of
       select() and pselect(), see select(2).

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       <?><?><?><?><?><?><?><?> <?> <?><?><?><?><?><?>
       pselect()  is useful if you are waiting for a signal as well as for
       file descriptor(s) to become ready for I/O.  Programs that receive
       signals normally use the signal handler only to raise a global flag.
       The global flag will indicate that the event must be processed in the
       main loop of the program.  A signal will cause the select()  (or
       pselect())  call to return with errno set to EINTR.  This behavior is
       essential so that signals can be processed in the main loop of the
       program, otherwise select()  would block indefinitely.

       Now, somewhere in the main loop will be a conditional to check the
       global flag.  So we must ask: what if a signal arrives after the
       conditional, but before the select()  call? The answer is that select()
       would block indefinitely, even though an event is actually pending.
       This race condition is solved by the pselect()  call.  This call can be
       used to set the signal mask to a set of signals that are to be received
       only within the pselect()  call.  For instance, let us say that the
       event in question was the exit of a child process.  Before the start of
       the main loop, we would block SIGCHLD using sigprocmask(2).  Our
       pselect()  call would enable SIGCHLD by using an empty signal mask.
       Our program would look like:

       static volatile sig_atomic_t got_SIGCHLD = 0;

       static void
       child_sig_handler(int sig)
       {
           got_SIGCHLD = 1;
       }

       int
       main(int argc, char *argv[])
       {
           sigset_t sigmask, empty_mask;
           struct sigaction sa;
           fd_set readfds, writefds, exceptfds;
           int r;

           sigemptyset(&sigmask);
           sigaddset(&sigmask, SIGCHLD);
           if (sigprocmask(SIG_BLOCK, &sigmask, NULL) == -1) {
               perror("sigprocmask");
               exit(EXIT_FAILURE);
           }

           sa.sa_flags = 0;
           sa.sa_handler = child_sig_handler;
           sigemptyset(&sa.sa_mask);
           if (sigaction(SIGCHLD, &sa, NULL) == -1) {
               perror("sigaction");
               exit(EXIT_FAILURE);
           }

           sigemptyset(&empty_mask);

           for (;;) {          /* main loop */
               /* Initialize readfds, writefds, and exceptfds
                  before the pselect() call. (Code omitted.) */

               r = pselect(nfds, &readfds, &writefds, &exceptfds,
                           NULL, &empty_mask);
               if (r == -1 && errno != EINTR) {
                   /* Handle error */
               }

               if (got_SIGCHLD) {
                   got_SIGCHLD = 0;

                   /* Handle signalled event here; e.g., wait() for all
                      terminated children. (Code omitted.) */
               }

               /* main body of program */
           }
       }

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       <?><?><?><?><?><?><?><?><?><?><?><?><?> select().

       1.  <?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?><?><?><?><?> select() <?><?><?>
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           <?><?><?><?><?><?><?><?>. <?><?><?><?> <?><?><?><?><?><?><?><?><?>
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           <?><?><?><?><?><?><?><?><?> <?> <?><?><?><?><?><?> <?><?><?>
           <?><?><?><?><?><?><?>.

       2.  <?><?><?> <?><?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?>
           nfds <?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?><?><?><?>, <?><?><?> <?><?><?>
           <?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?>.

       3.  <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?> <?><?>
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           select() <?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?>
           <?> <?><?><?><?><?><?><?><?><?><?><?><?><?><?><?>
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           <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?>.

       4.  <?><?><?><?><?> <?><?><?><?><?><?><?><?> <?><?> select()
           <?><?><?><?><?><?> <?><?><?><?> <?><?><?><?><?><?><?><?><?>
           <?><?><?> <?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?><?><?><?> <?><?> <?><?><?><?>
           <?><?><?><?><?><?><?>.

       5.  <?><?><?><?><?><?> read(2), recv(2), write(2) <?> send(2) <?><?>
           <?><?><?><?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?><?>/<?><?><?><?><?><?><?><?><?><?>
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           <?><?><?><?><?><?> <?><?><?><?> <?><?><?><?> <?><?> <?><?><?>.

       6.  <?><?><?><?><?><?><?> <?><?>
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           <?><?><?><?><?><?><?><?><?>/<?><?><?><?><?><?><?><?><?><?>
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           <?><?><?> <?><?> <?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?> <?>
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           <?> <?><?><?><?><?><?><?><?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?> <?><?><?><?><?> <?><?><?><?><?><?> 1024
           <?><?><?><?><?>, <?><?><?><?><?><?> <?><?><?><?><?> <?><?><?><?>
           <?><?><?><?><?> <?><?><?><?><?><?><?><?><?> <?><?>
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           <?><?><?><?><?><?> <?> <?><?><?><?><?> <?><?><?><?><?><?><?><?><?>
           <?><?><?><?>.

       7.  Calls to read(2), recv(2), write(2), send(2), and select() can fail
           with the error EINTR, and calls to read(2), recv(2), write(2), and
           send(2)  can fail with errno set to EAGAIN (EWOULDBLOCK).  These
           results must be properly managed (not done properly above).  If
           your program is not going to receive any signals, then it is
           unlikely you will get EINTR.  If your program does not set
           nonblocking I/O, you will not get EAGAIN.

       8.  <?><?><?><?><?><?><?> <?><?> <?><?><?><?><?><?><?><?><?> read(2),
           recv(2), write(2) <?><?><?> send(2) <?> <?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?> <?><?><?><?><?>.

       9.  <?><?><?><?> <?><?><?><?><?><?> read(2), recv(2), write(2) <?>
           send(2) <?><?><?><?><?><?><?><?><?><?><?> <?>
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           <?><?><?><?><?><?><?><?><?><?><?><?><?> <?> <?><?><?><?><?><?> 7.
           <?><?><?> <?><?><?><?> <?><?> <?><?><?><?><?><?><?> <?><?><?><?><?>
           <?><?><?><?><?><?> 0, <?><?><?> <?><?><?><?><?><?><?><?><?> <?><?>
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           <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?> <?>
           select() <?><?><?><?><?>. <?> <?><?><?><?><?><?><?> <?><?><?><?>
           <?> <?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?> <?>
           <?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?> <?> -1 <?><?><?>
           <?><?><?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?>
           <?><?><?><?><?><?><?><?><?> <?> <?><?><?><?><?>.

       10. <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?> <?><?><?><?><?><?> <?><?><?><?>
           <?><?><?><?><?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?>
           <?><?><?><?><?><?> <?><?><?><?><?> <?><?><?><?><?><?> select(),
           <?><?><?> <?><?><?> <?><?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?><?>. <?><?><?><?><?><?> pselect() <?><?>
           <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?>.

       11. <?><?><?> <?><?><?> select() <?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?><?>,
           <?><?> <?><?><?> <?><?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?>
           <?> <?><?><?><?><?> <?><?><?><?><?><?> <?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?>
           <?><?><?><?><?><?><?><?><?><?><?><?><?><?><?><?><?><?>
           <?><?><?><?><?> <?><?><?><?><?><?> <?><?><?><?><?><?><?>.

<?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?> select(2).

<?><?><?><?><?><?><?><?><?>
       <?> <?><?><?><?><?> <?><?><?><?><?><?>, <?><?><?>
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       <?><?><?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?>,
       <?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?> <?> select().
       <?><?><?><?><?> select() <?><?><?><?><?> <?><?><?><?><?><?><?><?><?>
       <?><?><?> <?><?><?><?><?><?><?><?><?><?><?><?> <?>
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       <?><?><?><?><?><?><?>, <?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?> <?> <?><?><?><?><?><?> <?><?><?><?><?><?>.

       <?><?><?><?><?><?><?><?><?> <?><?><?><?><?> poll(2) <?><?><?><?><?>
       <?><?><?><?><?> <?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?><?><?><?><?>, <?><?><?> <?>
       select() <?> <?><?><?><?><?><?> <?><?><?><?><?>
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       <?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?> <?><?><?> select().

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       epoll(7) <?><?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?> <?><?><?>
       <?><?><?><?><?><?><?><?> <?><?> <?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?> select(2) <?> poll(2).

<?><?><?><?><?><?><?>
       <?><?><?> <?><?><?><?><?><?>, <?><?><?><?><?><?><?> <?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?> select(). <?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?>
       <?><?><?><?><?> TCP <?> <?><?><?><?><?><?>.

       #include <arpa/inet.h>
       #include <errno.h>
       #include <netinet/in.h>
       #include <signal.h>
       #include <stdio.h>
       #include <stdlib.h>
       #include <string.h>
       #include <sys/select.h>
       #include <sys/socket.h>
       #include <unistd.h>

       static int forward_port;

       #undef max
       #define max(x, y) ((x) > (y) ? (x) : (y))

       static int
       listen_socket(int listen_port)
       {
           int                 lfd;
           int                 yes;
           struct sockaddr_in  addr;

           lfd = socket(AF_INET, SOCK_STREAM, 0);
           if (lfd == -1) {
               perror("socket");
               return -1;
           }

           yes = 1;
           if (setsockopt(lfd, SOL_SOCKET, SO_REUSEADDR,
                          &yes, sizeof(yes)) == -1)
           {
               perror("setsockopt");
               close(lfd);
               return -1;
           }

           memset(&addr, 0, sizeof(addr));
           addr.sin_port = htons(listen_port);
           addr.sin_family = AF_INET;
           if (bind(lfd, (struct sockaddr *) &addr, sizeof(addr)) == -1) {
               perror("bind");
               close(lfd);
               return -1;
           }

           printf("accepting connections on port %d\n", listen_port);
           listen(lfd, 10);
           return lfd;
       }

       static int
       connect_socket(int connect_port, char *address)
       {
           int                 cfd;
           struct sockaddr_in  addr;

           cfd = socket(AF_INET, SOCK_STREAM, 0);
           if (cfd == -1) {
               perror("socket");
               return -1;
           }

           memset(&addr, 0, sizeof(addr));
           addr.sin_port = htons(connect_port);
           addr.sin_family = AF_INET;

           if (!inet_aton(address, (struct in_addr *) &addr.sin_addr.s_addr)) {
               fprintf(stderr, "inet_aton(): bad IP address format\n");
               close(cfd);
               return -1;
           }

           if (connect(cfd, (struct sockaddr *) &addr, sizeof(addr)) == -1) {
               perror("connect()");
               shutdown(cfd, SHUT_RDWR);
               close(cfd);
               return -1;
           }
           return cfd;
       }

       #define SHUT_FD1 do {                                \
                            if (fd1 >= 0) {                 \
                                shutdown(fd1, SHUT_RDWR);   \
                                close(fd1);                 \
                                fd1 = -1;                   \
                            }                               \
                        } while (0)

       #define SHUT_FD2 do {                                \
                            if (fd2 >= 0) {                 \
                                shutdown(fd2, SHUT_RDWR);   \
                                close(fd2);                 \
                                fd2 = -1;                   \
                            }                               \
                        } while (0)

       #define BUF_SIZE 1024

       int
       main(int argc, char *argv[])
       {
           int      h;
           int      ready, nfds;
           int      fd1 = -1, fd2 = -1;
           int      buf1_avail = 0, buf1_written = 0;
           int      buf2_avail = 0, buf2_written = 0;
           char     buf1[BUF_SIZE], buf2[BUF_SIZE];
           fd_set   readfds, writefds, exceptfds;
           ssize_t  nbytes;

           if (argc != 4) {
               fprintf(stderr, "Usage\n\tfwd <listen-port> "
                       "<forward-to-port> <forward-to-ip-address>\n");
               exit(EXIT_FAILURE);
           }

           signal(SIGPIPE, SIG_IGN);

           forward_port = atoi(argv[2]);

           h = listen_socket(atoi(argv[1]));
           if (h == -1)
               exit(EXIT_FAILURE);

           for (;;) {
               nfds = 0;

               FD_ZERO(&readfds);
               FD_ZERO(&writefds);
               FD_ZERO(&exceptfds);
               FD_SET(h, &readfds);
               nfds = max(nfds, h);

               if (fd1 > 0 && buf1_avail < BUF_SIZE)
                   FD_SET(fd1, &readfds);
                   /* Note: nfds is updated below, when fd1 is added to
                      exceptfds. */
               if (fd2 > 0 && buf2_avail < BUF_SIZE)
                   FD_SET(fd2, &readfds);

               if (fd1 > 0 && buf2_avail - buf2_written > 0)
                   FD_SET(fd1, &writefds);
               if (fd2 > 0 && buf1_avail - buf1_written > 0)
                   FD_SET(fd2, &writefds);

               if (fd1 > 0) {
                   FD_SET(fd1, &exceptfds);
                   nfds = max(nfds, fd1);
               }
               if (fd2 > 0) {
                   FD_SET(fd2, &exceptfds);
                   nfds = max(nfds, fd2);
               }

               ready = select(nfds + 1, &readfds, &writefds, &exceptfds, NULL);

               if (ready == -1 && errno == EINTR)
                   continue;

               if (ready == -1) {
                   perror("select()");
                   exit(EXIT_FAILURE);
               }

               if (FD_ISSET(h, &readfds)) {
                   socklen_t addrlen;
                   struct sockaddr_in client_addr;
                   int fd;

                   addrlen = sizeof(client_addr);
                   memset(&client_addr, 0, addrlen);
                   fd = accept(h, (struct sockaddr *) &client_addr, &addrlen);
                   if (fd == -1) {
                       perror("accept()");
                   } else {
                       SHUT_FD1;
                       SHUT_FD2;
                       buf1_avail = buf1_written = 0;
                       buf2_avail = buf2_written = 0;
                       fd1 = fd;
                       fd2 = connect_socket(forward_port, argv[3]);
                       if (fd2 == -1)
                           SHUT_FD1;
                       else
                           printf("connect from %s\n",
                                  inet_ntoa(client_addr.sin_addr));

                       /* Skip any events on the old, closed file
                          descriptors. */

                       continue;
                   }
               }

               /* NB: read OOB data before normal reads. */

               if (fd1 > 0 && FD_ISSET(fd1, &exceptfds)) {
                   char c;

                   nbytes = recv(fd1, &c, 1, MSG_OOB);
                   if (nbytes < 1)
                       SHUT_FD1;
                   else
                       send(fd2, &c, 1, MSG_OOB);
               }
               if (fd2 > 0 && FD_ISSET(fd2, &exceptfds)) {
                   char c;

                   nbytes = recv(fd2, &c, 1, MSG_OOB);
                   if (nbytes < 1)
                       SHUT_FD2;
                   else
                       send(fd1, &c, 1, MSG_OOB);
               }
               if (fd1 > 0 && FD_ISSET(fd1, &readfds)) {
                   nbytes = read(fd1, buf1 + buf1_avail,
                                 BUF_SIZE - buf1_avail);
                   if (nbytes < 1)
                       SHUT_FD1;
                   else
                       buf1_avail += nbytes;
               }
               if (fd2 > 0 && FD_ISSET(fd2, &readfds)) {
                   nbytes = read(fd2, buf2 + buf2_avail,
                                 BUF_SIZE - buf2_avail);
                   if (nbytes < 1)
                       SHUT_FD2;
                   else
                       buf2_avail += nbytes;
               }
               if (fd1 > 0 && FD_ISSET(fd1, &writefds) && buf2_avail > 0) {
                   nbytes = write(fd1, buf2 + buf2_written,
                                  buf2_avail - buf2_written);
                   if (nbytes < 1)
                       SHUT_FD1;
                   else
                       buf2_written += nbytes;
               }
               if (fd2 > 0 && FD_ISSET(fd2, &writefds) && buf1_avail > 0) {
                   nbytes = write(fd2, buf1 + buf1_written,
                                  buf1_avail - buf1_written);
                   if (nbytes < 1)
                       SHUT_FD2;
                   else
                       buf1_written += nbytes;
               }

               /* Check if write data has caught read data. */

               if (buf1_written == buf1_avail)
                   buf1_written = buf1_avail = 0;
               if (buf2_written == buf2_avail)
                   buf2_written = buf2_avail = 0;

               /* One side has closed the connection, keep
                  writing to the other side until empty. */

               if (fd1 < 0 && buf1_avail - buf1_written == 0)
                   SHUT_FD2;
               if (fd2 < 0 && buf2_avail - buf2_written == 0)
                   SHUT_FD1;
           }
           exit(EXIT_SUCCESS);
       }

       <?><?><?><?><?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?> <?><?><?><?><?>,
       <?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?>
       TCP, <?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?> (OOB)
       <?><?><?><?><?><?>, <?><?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?> telnet. <?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?> <?><?> <?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?>
       <?><?><?><?><?><?><?>. <?><?><?><?><?><?><?><?>, <?><?>
       <?><?><?><?><?><?>, <?><?><?> <?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?> fork(2) <?>
       <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?> <?><?><?><?>
       <?><?><?> <?><?><?><?><?><?><?> <?><?><?><?><?><?>. <?><?>
       <?><?><?><?><?> <?><?><?><?> <?><?><?> <?><?><?><?><?><?><?>, <?><?><?>
       <?><?><?><?><?><?><?>. <?><?><?><?><?><?> <?><?><?><?><?>
       <?><?><?><?><?> <?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?>-<?><?><?><?><?><?> <?> <?><?><?><?><?><?><?> fcntl(2).
       <?><?><?> <?><?><?><?><?> <?><?><?><?><?> <?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?> <?><?>-<?><?> <?><?><?><?>, <?><?><?>
       <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?>.

       The program does not handle more than one simultaneous connection at a
       time, although it could easily be extended to do this with a linked
       list of buffers--one for each connection.  At the moment, new
       connections cause the current connection to be dropped.

<?><?>. <?><?><?><?><?>
       accept(2), connect(2), poll(2), read(2), recv(2), select(2), send(2),
       sigprocmask(2), write(2), epoll(7)

<?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?> <?><?><?><?><?><?><?> <?><?><?><?>
       <?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?> <?><?><?>
       <?><?><?><?><?><?> Alexander Golubev <fatzer2@gmail.com>, Azamat
       Hackimov <azamat.hackimov@gmail.com>, Hotellook, Nikita
       <zxcvbnm3230@mail.ru>, Spiros Georgaras <sng@hellug.gr>, Vladislav
       <ivladislavefimov@gmail.com>, Yuri Kozlov <yuray@komyakino.ru> <?>
       <?><?><?><?> <?><?><?><?><?><?> <pavia00@gmail.com>

       <?><?><?><?> <?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?><?><?>;
       <?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?> GNU
       <?><?><?><?><?><?> 3 <https://www.gnu.org/licenses/gpl-3.0.html>
       <?><?><?> <?><?><?><?><?> <?><?><?><?><?><?><?>, <?><?><?><?><?>
       <?><?><?><?><?><?> <?><?> <?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?>. <?><?> <?><?>
       <?><?><?><?><?> <?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?><?><?><?><?>.

       <?><?><?><?> <?><?> <?><?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?>
       <?> <?><?><?><?><?><?><?><?> <?><?><?><?> <?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?><?><?><?><?><?>, <?><?><?><?><?><?><?><?><?><?>,
       <?><?><?><?><?><?><?><?><?> <?><?><?><?><?><?><?><?><?><?><?>
       <?><?><?><?><?><?> <?><?> <man-pages-ru-talks@lists.sourceforge.net>.

Linux man-pages 6.06  31 <?><?><?><?><?><?><?> 2023 <?>.         SELECT_TUT(2)