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)