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t_open - establish a transport endpoint
#include <xti.h> #include <fcntl.h> int t_open(const char *name, int oflag, struct t_info *info);
This routine is part of the XTI interfaces which evolved from the TLI interfaces. XTI represents the future evolution of these interfaces. However, TLI interfaces are supported for compatibility. When using a TLI routine that has the same name as an XTI routine, the tiuser.h header file must be used. Refer to the TLI COMPATIBILITY section for a description of differences between the two interfaces.
The t_open() function must be called as the first step in the initialization of a transport endpoint. This function establishes a transport endpoint by supplying a transport provider identifier that indicates a particular transport provider, that is, transport protocol, and returning a file descriptor that identifies that endpoint.
The argument name points to a transport provider identifier and oflag identifies any open flags, as in open(2). The argument oflag is constructed from O_RDWR optionally bitwise inclusive-OR'ed with O_NONBLOCK. These flags are defined by the header <fcntl.h>. The file descriptor returned by t_open() 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 t_info structure. This argument points to a t_info which contains the following members:
t_scalar_t addr; /* max size of the transport protocol address */
t_scalar_t options; /* max number of bytes of */
/* protocol-specific options */
t_scalar_t tsdu; /* max size of a transport service data */
/* unit (TSDU) */
t_scalar_t etsdu; /* max size of an expedited transport */
/* service data unit (ETSDU) */
t_scalar_t connect; /* max amount of data allowed on */
/* connection establishment functions */
t_scalar_t discon; /* max amount of data allowed on */
/* t_snddis() and t_rcvdis() functions */
t_scalar_t servtype; /* service type supported by the */
/* transport provider */
t_scalar_t flags; /* other info about the transport provider */
The values of the fields have the following meanings:
addr
options
tsdu
etsdu
connect
discon
servtype
flags
If a transport user is concerned with protocol independence, the above sizes may be accessed to determine how large the buffers must be to hold each piece of information. Alternatively, the t_alloc(3NSL) 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:
T_COTS
T_COTS_ORD
T_CLTS
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 t_open().
A valid file descriptor is returned upon successful completion. Otherwise, a value of -1 is returned and t_errno is set to indicate an error.
On failure, t_errno is set to the following:
TBADFLAG
TBADNAME
TPROTO
TSYSERR
The XTI and TLI interface definitions have common names but use different header files. This and other semantic differences between the two interfaces are described in the subsections below.
The XTI interfaces use the xti.h TLI interfaces should not use this header. They should use the header:
#include <tiuser.h>
The t_errno values TPROTO and TBADNAME can be set by the XTI interface but cannot be set by the TLI interface.
For TLI , the t_info structure referenced by info lacks the following structure member:
t_scalar_t flags; /* other info about the transport provider */
This member was added to struct t_info in the XTI interfaces.
When a value of -1 is observed as the return value in various t_info structure members, it signifies that the transport provider can handle an infinite length buffer for a corresponding attribute, such as address data, option data, TSDU (octet size), ETSDU (octet size), connection data, and disconnection data. The corresponding structure members are addr, options, tsdu, estdu, connect, and discon, respectively.
See attributes(5) for descriptions of the following attributes:
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open(2), attributes(5)
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Created 1996-2024 by Maxim Chirkov Добавить, Поддержать, Вебмастеру |