t_rcvudata(3N) manual page
Table of Contents
t_rcvudata - receive a data unit
cc [ flag ... ] file ... -lnsl
[ library ... ]
#include <tiuser.h>
int t_rcvudata(int fildes, struct t_unitdata
*unitdata, int *flags);
MT-Safe
This function is used
in connectionless mode to receive a data unit from another transport user.
fildes identifies the local transport endpoint through which data will
be received, unitdata holds information associated with the received data
unit, and flags is set on return to indicate that the complete data unit
was not received. unitdata points to a t_unitdata structure containing the
following members:
struct netbuf addr;
struct netbuf opt;
struct netbuf udata;
The maxlen (see netbuf in t_connect(3N)
) field of addr, opt, and udata
must be set before issuing this function to indicate the maximum size of
the buffer for each.
On return from this call, addr specifies the protocol
address of the sending user, opt identifies protocol-specific options that
were associated with this data unit, and udata specifies the user data
that was received.
By default, t_rcvudata() operates in synchronous mode
and will wait for a data unit to arrive if none is currently available.
However, if O_NDELAY
or O_NONBLOCK
is set (using t_open(3N)
or fcntl(2)
),
t_rcvudata() will execute in asynchronous mode and will fail if no data
units are available.
If the buffer defined in the udata field of unitdata
is not large enough to hold the current data unit, the buffer will be filled
and T_MORE
will be set in flags on return to indicate that another t_rcvudata()
should be issued to retrieve the rest of the data unit. Subsequent t_rcvudata()
call(s) will return zero for the length of the address and options until
the full data unit has been received.
t_rcvudata() returns
0 on successful completion. On failure t_rcvudata() returns -1, t_errno is
set to indicate the error, and possibly errno is set.
On failure,
t_errno will be set to one of the following:
- TBADF
- The specified file
descriptor does not refer to a transport endpoint.
- TBUFOVFLW
- The number
of bytes allocated for the incoming protocol address or options is greater
than zero but not sufficient to store the information. The unit data information
to be returned in unitdata will be discarded.
- TLOOK
- An asynchronous event
has occurred on this transport endpoint and requires immediate attention.
- TNODATA
- O_NDELAY
or O_NONBLOCK
was set, but no data units are currently
available from the transport provider.
- TNOTSUPPORT
- This function is not
supported by the underlying transport provider.
- TSYSERR
- A system error
has occurred during execution of this function, errno will be set to the
specific error.
fcntl(2)
, t_connect(3N)
, t_rcvuderr(3N)
, t_sndudata(3N)
This interface is safe in multithreaded applications.
Table of Contents
![[Go to CFHT Home Page]](/images/cfht-icon.gif){kind=icon}
Man Pages 
Back to Software Index 
Manpage Top Level