dglopen(3G)                                                        dglopen(3G)



NAME
     dglopen - opens a Graphics Library connection to a graphics server

C SPECIFICATION
     long dglopen(svname, type)
     String svname;
     long type;

PARAMETERS
     svname   expects a pointer to the name of the graphics server to which
              you want to open a connection.

              For a successful connection, the client host must have
              permission to connect to the graphics server.  Authentication is
              accomplished via the same mechanisms as for X clients.  See
              xhost(1) for further details.

              The svname parameter has the following syntax:

              [[username ]password@]hostname[:server[.screen]]

              where hostname is an internet host name recognized by
              gethostname(3N).  server and screen are ignored, and both are
              set to 0.

              For DECnet connections, if the server account has a password,
              this password must be specified by including username and
              password.  This password is used only for opening the DECnet
              connection; the local and remote accounts must still be
              equivalent in the rlogin sense.

     type     expects a symbolic constant that specifies the kind of
              connection.  There are three defined constants for this
              parameter:

              DGLLOCAL indicates a direct connection to the local graphics
              hardware.  This type of connection is not supported on client
              machines without IRIS graphics hardware.

              DGLTSOCKET indicates a remote connection via TCP/IP.

              DGL4DDN indicates a remote connection via DECnet.

FUNCTION RETURN VALUE
     If the connection succeeds, the returned value of the function is a non-
     negative integer, serverid, that identifies the graphics server.  If the
     connection failed, the returned value for the function is a negative
     integer.  The absolute value of a negative returned value is either a
     standard error value (defined in <errno.h>) or one of several error
     returns associated specifically with dglopen:





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dglopen(3G)                                                        dglopen(3G)



     ENODEV      type is not a valid connection type.

     EACCES      login incorrect or permission denied.

     EMFILE      too many graphics connections are currently open.

     ENOPROTOOPT DGL service not found in /etc/services.

     ERANGE      invalid or unrecognizable number representation.

     EPROTONOSUPPORT
                 DGL version mismatch.

     ESRCH       the window manager is not running on the server.

DESCRIPTION
     dglopen opens a Graphics Library connection to a graphics server
     (svname).  After a connection is open, all graphics preferences, input,
     and output are directed to that connection.  This direction is continued
     until either the connection is closed, another connection is opened, or a
     different connection is selected.  A different connection can be selected
     by calling a subroutine that takes a graphics window identifier as an
     input parameter, e.g. winset.  The server connection associated with that
     graphics window identifier becomes the current connection.  To close a
     connection, call dglclose with the server identifier returned by dglopen.

     If a remote server error occurs, the graphics application may exit with a
     status value EIO and produce the following error message:

          dgl error (comm): read returned 0

SEE ALSO
     dglclose, finish, gflush, winopen, winset, scrnselect

     rlogin(1C), gethostbyname(3N) in the IRIS-4D User's Reference Manual

NOTES
     This routine is available only in immediate mode.

     This routine is available in both the GL and DGL libraries.  However, the
     DGLLOCAL connection type is not supported by the DGL library.














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