t_alloc(3)t_alloc(3)NAMEt_alloc() - allocate transport function library structure
SYNOPSIS
— or —
DESCRIPTION
The function dynamically allocates memory for the various transport
function argument structures as specified below. This function will
allocate memory for the specified structure and will also allocate mem‐
ory for buffers referenced by the structure.
The structure to allocate is specified by struct_type and must be one
of the following:
T_BIND struct t_bind
T_CALL struct t_call
T_DIS struct t_discon
T_INFO struct t_info
T_OPTMGMT struct t_optmgmt
T_UDERROR struct t_uderr
T_UNITDATA struct t_unitdata
where each of these structures may subsequently be used as an argument
to one or more transport functions.
Each of the above structures, except T_INFO, contains at least one
field of type For each field of this type, the user may specify that
the buffer for that field should be allocated as well. The length of
the buffer allocated will be equal to or greater than the appropriate
size returned in the info argument of or The relevant fields of the
info argument are described in the following list. The fields argument
specifies which buffer to allocate, where the argument is the bitwise-
OR of any of the following:
The addr field of the or structures.
The opt field of the or structures.
The udata field of the or structures.
All relevant fields of the given structure.
Fields which are not supported by e transport
provider specified by fd will not be allocated
(info values are <= 0).
For each field specified in fields, will allocate memory for the buffer
associated with the field, and initialize the len field to zero and the
buf pointer and maxlen field accordingly. Since the length of the buf‐
fer allocated will be based on the same size information that is
returned to the user on or fd must refer to the transport endpoint
through which the newly allocated structure will be passed. In this
way the appropriate size information can be accessed. If the size
value associated with any specified field is −1 or −2 ( see t_open(3)
or t_getinfo(3)), will be unable to determine the size of the buffer to
allocate and will fail, setting to and to For any field not specified
in fields, buf will be set to a null pointer and maxlen will be set to
zero.
Use of to allocate structures will help ensure the compatibility of
user programs with future releases of the transport interface func‐
tions.
Valid States
All, apart from
Fork Safety
is not fork-safe.
RETURN VALUE
Upon successful completion, returns a pointer to the newly allocated
structure. On failure, a null pointer is returned.
ERRORS
On failure, is set to one of the following:
fd, the specified endpoint identifier, does not refer to a
transport endpoint.
A system error has occurred during execution of this function.
(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
Unsupported struct_type requested. This can include a request for a
structure type which is inconsistent with the transport
provider type specified, that is, connection-oriented or
connectionless.
SEE ALSOt_free(3), t_getinfo(3), t_open(3), thread_safety(5).
STANDARDS CONFORMANCEt_alloc(3)
