t_sync(S)                 (TLI/XTI) 6 January 1993                 t_sync(S)


 Name

    t_sync - synchronize transport library

 Syntax


    TLI syntax


    cc  . . .  -lnsls


    #include <sys/tiuser.h>

    int t_sync (fd)
    int fd;


    XTI syntax


    cc  . . .  -lxti


    #include <xti.h>

    int t_sync (fd)
    int fd;


 Description

    For the transport endpoint specified by fd, tsync synchronizes the data
    structures managed by the transport library with information from the
    underlying transport provider.  In doing so, it can convert a raw file
    descriptor (obtained via open(S), dup(S), or as a result of a fork(S) and
    exec(S)) to an initialized transport endpoint, assuming that file
    descriptor referenced a transport provider.  This function also allows
    two cooperating processes to synchronize their interaction with a trans-
    port provider.

    For example, if a process forks a new process and issues an exec, the new
    process must issue a tsync to build the private library data structure
    associated with a transport endpoint and to synchronize the data struc-
    ture with the relevant provider information.

    It is important to remember that the transport provider treats all users
    of a transport endpoint as a single user.  If multiple processes are
    using the same endpoint, they should coordinate their activities so as
    not to violate the state of the provider.  tsync returns the current
    state of the provider to the user, thereby enabling the user to verify
    the state before taking further action.  This coordination is only valid
    among cooperating processes; it is possible that a process or an incoming
    event could change the provider's state after a tsync is issued.

    If the provider is undergoing a state transition when tsync is called,
    the function fails.

    On failure, terrno may be set to one of the following:

    [TBADF]            The specified file descriptor is a valid open file
                       descriptor but does not refer to a transport endpoint.

    [TSTATECHNG]       The transport provider is undergoing a state change.

    [TSYSERR]          A system error occurred during execution of this func-
                       tion.  One possibility is an I/O error and is indi-
                       cated by EIO being set in errno.

 Diagnostics

    The tsync function returns the state of the transport provider on suc-
    cessful completion and -1 on failure, and terrno is set to indicate the
    error.  The state returned may be one of the following:

    TDATAXFER     data transfer

    TIDLE         idle

    TINCON        incoming connection pending

    TINREL        incoming orderly release (waiting for an orderly release
                   request).

    TOUTCON       outgoing connection pending

    TOUTREL       outgoing orderly release (waiting for an orderly release
                   indication)

    TUNBND        unbound


 See also

    dup(S), exec(S), fork(S), open(S)

 Standards conformance

    tsync is conformant with:
    AT&T SVID Issue 2;
    X/Open Portability Guide, Issue 3, 1989;
    and Intel386 Binary Compatibility Specification, Edition 2 (iBCSe2).