t_open(3)						     Library Functions Manual							 t_open(3)

NAME

       t_open() - establish a transport endpoint

SYNOPSIS

DESCRIPTION

       The  function  must  be called as the first step in the initialization of a transport endpoint.	This function establishes a transport end-
       point by opening a file that identifies a particular transport provider and returning a file descriptor that identifies that endpoint.

       The argument name points to a file name that identifies a transport provider.  When using HP XTI to connect to the OSI protocol stack, name
       must  be  for  the connection-mode service, or for the connectionless service. When using HP XTI to connect to the TCP protocol stack, name
       should be For UDP, name should be (See also the section.)  For TLI, use the device file name of the transport provider desired.	Note  that
       HP TCP/UDP/IP and HP OSI COTS and CLTS only support XTI.

       oflag  identifies  any open flags (as in and is constructed from optionally or-ed with These flags are defined by the header file returns a
       file descriptor that will be used by all subsequent functions to identify the particular local transport endpoint.

       This function also returns various default characteristics of the underlying transport protocol by setting fields in the  structure.   This
       argument points to a which contains the following members:

       The values of the fields have the following meanings:

       addr	      A value greater than or equal to zero indicates the maximum size of a transport protocol address.

		      A value of -1 specifies that there is no limit on the address size.

		      A value of -2 specifies that the transport provider does not provide user access to transport protocol addresses.

       options	      A  value	greater  than or equal to zero indicates the maximum number of bytes of protocol-specific options supported by the
		      provider.

		      A value of -1 specifies that there is no limit on the option size.

		      A value of -2 specifies that the transport provider does not support user-settable options.

       tsdu	      A value greater than zero specifies the maximum size of a transport service data unit (TSDU).

		      A value of zero specifies that the transport provider does not support the concept of TSDU, although  it	does  support  the
		      sending of a data stream with no logical boundaries preserved across a connection.

		      A value of -1 specifies that there is no limit on the size of a TSDU.

		      A value of -2 specifies that the transfer of normal data is not supported by the transport provider.

       etsdu	      A value greater than zero specifies the maximum size of an expedited transport service data unit (ETSDU).

		      A  value	of  zero specifies that the transport provider does not support the concept of ETSDU, although it does support the
		      sending of an expedited data stream with no logical boundaries preserved across a connection.

		      A value of -1 specifies that there is no limit on the size of an ETSDU.

		      A value of -2 specifies that the transfer of expedited data is not supported by the transport provider.

       connect	      A value greater than or equal to zero specifies the maximum amount of data that may be associated with the connection estab-
		      lishment functions and

		      A value of -1 specifies that there is no limit on the amount of data sent during connection establishment.

		      A value of -2 specifies that the transport provider does not allow data to be sent with connection establishment functions.

       discon	      A value greater than or equal to zero specifies the maximum amount of data that may be associated with the and functions.

		      A value of -1 specifies that there is no limit on the amount of data sent with these abortive release functions.

		      A value of -2 specifies that the transport provider does not allow data to be sent with the abortive release functions.

       servtype       This field specifies the service type supported by the transport provider, as described below.

       flags	      This  is a bit field used to specify other information about the transport provider.  If the bit is set in flags, this indi-
		      cates the underlying transport provider supports the sending of zero-length TSDUs.  See Appendix A, "ISO Transport  Protocol
		      Information,"  of  the  manual  from  X/Open Company Limited for a discussion of the separate issue of zero-length fragments
		      within a TSDU.

       If a transport user is concerned with protocol independence, the above sizes may be accessed to determine how large the buffer must  be	to
       hold  each  piece  of information.  Alternatively, the function may be used to allocate these buffers.  An error will result if a transport
       user exceeds the allowed data size on any function.

       The servtype field of info specifies one of the following values on return:

       The transport provider supports a connection-mode service but does not
		      support the optional orderly release facility.

       The transport provider supports a connection-mode service with the
		      optional orderly release facility.

       The transport provider supports a connectionless-mode service.
		      For this service type, will return -2 for etsdu, connect, and discon.

		      A single transport endpoint may support only one of the above services at one time.

       If info is set to a null pointer by the transport user, no protocol information is returned by

   Obsolescent Interfaces
       When using TCP and UDP through HP XTI, name can be and respectively.  These names are supported for backward-compatibility purposes.   They
       might not be supported in future releases, and they should be replaced with and respectively.

   Fork Safety
       is not fork-safe.

RETURN VALUE

       A valid endpoint identifier is returned upon successful completion.  Otherwise, a value of -1 is returned and is set to indicate an error.

       HP OSI does not support the servtype.

ERRORS

       On error, is set to one of the following:

       [TBADFLAG]     An invalid flag is specified.

       [TBADNAME]     Invalid transport provider name.

       [TSYSERR]      A system error has occurred during execution of this function.

       [TPROTO]       (XTI  only)  This  error indicates that a communication problem has been detected between XTI and the transport provider for
		      which there is no suitable XTI (

SEE ALSO

       open(2), t_sync(3), thread_safety(5).

STANDARDS CONFORMANCE

																	 t_open(3)