#include	<starlet.h>
#include	<lib$routines.h>
#include <descrip.h>		/* Descriptor structure definitions  */
#include <libdef.h>		/* LIB RTL symbol definitions         */
#include <stdio.h>		/* Standard C symbol definitions     */
#include <ssdef.h>		/* System Service status code def'ns */
#include <cmbdef.h>		/* CREMBX definitions                  */
#include <agndef.h>		/* ASSIGN definitions                  */
#include <iodef.h>		/* I/O definitions                      */

  #define $ARRAY_DESCRIPTOR(name,size,array_name)                       \
       char array_name[ size ];                                             \
       struct dsc$descriptor_s name =                                      \
          { size, DSC$K_DTYPE_T, DSC$K_CLASS_S, array_name }

  main()

  {
  # define max_msg_len 256
  $DESCRIPTOR(mailbox_name_desc,"MAILBOX_EXAMPLE");
  $ARRAY_DESCRIPTOR(read_buffer_desc,max_msg_len,read_buffer);
  int status, mailbox_channel;
  int true=1, false = 0;
  struct io_status_block {                            /*  I/O status block */
       short int condition;
       short int count;
       int dev;
       } iosb;

  /*
   * Create a permanent mailbox with a READONLY channel.  It's logical name
   *  will be entered into the LNM$PERMANENT_MAILBOX logical name table.
   */


sys$crembx(1,&mailbox_channel,0,0,0,0,&mailbox_name_desc,CMB$M_READONLY);

  /*
   * Mark it for deletion
   */
sys$delmbx(mailbox_channel);

  /*
   * Loop forever, first waiting til a WRITE channel is assigned to the mailbox
   * and then reading data from it until the WRITER deassigns.
   */
       while (TRUE)
       {
          /* First, check to see if there is a WRITER assigned to the mailbox */
           status = sys$qiow (
                0,
                mailbox_channel,
                IO$_SENSEMODE|IO$M_WRITERCHECK,
                &iosb,
                0,0,
                0,0,0,0,0,0);

           /* If there was no WRITER, then wait for one.*/
           if (iosb.condition == SS$_NOWRITER)
           status = sys$qiow (
                0,
                mailbox_channel,
                IO$_SETMODE|IO$M_WRITERWAIT,
                &iosb,
                0,0,
                0,0,0,0,0,0);

           /*
             * While the status is good, READ from the mailbox, and write it to
             */
           while (status == SS$_NORMAL)
           {
                status = sys$qiow(
                     0,
                     mailbox_channel,
                     IO$_READVBLK|IO$M_WRITERCHECK,
                     &iosb,
                     0,0,
                     read_buffer_desc.dsc$a_pointer,max_msg_len,
                     0,0,0,0);
                status=iosb.condition;
                read_buffer_desc.dsc$w_length = iosb.count;
                lib$put_output(&read_buffer_desc);
           }
       }
  }