JIOCTL(9.4)                                           JIOCTL(9.4)

     NAME
          jioctl - jerq ioctl requests

     SYNOPSIS
          #include /usr/jerq/include/jioctl.h

          ioctl(fd, JMUX, 0)

          ioctl(fd, request, win)
          struct winsize *win;

     DESCRIPTION
          Mux(9.1) supports several jerq-specific ioctl(2) requests
          for Unix programs attached to layers.  The requests are:
          312144.if 408.sp40u
          JMUX returns 0 if file descriptor fd is connected to a mux
               layer, -1 otherwise.

          JTERM
               resets the layer connected to fd to the default termi-
               nal program.

          JBOOT
               initiates the down-load protocol to replace the layer's
               terminal program.  Usually called by 32ld(9.1).

          JZOMBOOT
               is the same as JBOOT, but disables execution of the
               program when the download is complete (see the -z flag
               of 32ld).

          JWINSIZE
               returns, in the location pointed to by the third argu-
               ment, a structure describing the size of the layer con-
               nected to fd. The structure is:

               struct winsize {
                      char   bytesx, bytesy;  /* size in characters */
                      short  bitsx, bitsy;    /* size in pixels */
               };

          JEXIT
               causes mux to exit.

     SEE ALSO
          32ld(9.1), mux(9.1), ioctl(2)