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cc [ flag ... ] file ... -lnsl [ library ... ]
#include <tiuser.h>
int t_snd(int fildes, char *buf, unsigned nbytes, int flags);
MT-Safe
By default, t_snd() operates in synchronous mode and may wait if flow control restrictions prevent the data from being accepted by the local transport provider at the time the call is made. However, if O_NDELAY or O_NONBLOCK is set (using t_open(3N) or fcntl(2) ), t_snd() will execute in asynchronous mode, and will fail immediately if there are flow control restrictions.
Even when there are no flow control restrictions, t_snd() will wait if STREAMS internal resources are not available, regardless of the state of O_NDELAY or O_NONBLOCK .
On successful completion, t_snd() returns the number of bytes accepted by the transport provider. Normally this will equal the number of bytes specified in nbytes. However, if O_NDELAY or O_NONBLOCK is set, it is possible that only part of the data will be accepted by the transport provider. In this case, t_snd() will set T_MORE for the data that was sent (see below) and will return a value less than nbytes. If nbytes is zero and sending of zero bytes is not supported by the underlying transport provider, t_snd() will return -1 with t_errno set to TBADDATA . A return value of zero indicates that the request to send a zero-length data message was sent to the provider.
If T_EXPEDITED is set in flags, the data will be sent as expedited data, and will be subject to the interpretations of the transport provider.
If T_MORE is set in flags, or is set as described above, an indication is sent to the transport provider that the transport service data unit (TSDU ) or expedited transport service data unit (ETSDU ) is being sent through multiple t_snd() calls. Each t_snd() with the T_MORE flag set indicates that another t_snd() will follow with more data for the current TSDU . The end of the TSDU (or ETSDU ) is identified by a t_snd() call with the T_MORE flag not set. Use of T_MORE enables a user to break up large logical data units without losing the boundaries of those units at the other end of the connection. The flag implies nothing about how the data is packaged for transfer below the transport interface. If the transport provider does not support the concept of a TSDU as indicated in the info argument on return from t_open(3N) or t_getinfo(3N) , the T_MORE flag is not meaningful and should be ignored.
The size of each TSDU or ETSDU must not exceed the limits of the transport provider as returned by t_open(3N) or t_getinfo(3N) . If the size is exceeded, a TSYSERR with system error EPROTO will occur. However, the t_snd() may not fail because EPROTO errors may not be reported immediately. In this case, a subsequent call that accesses the transport endpoint will fail with the associated TSYSERR .
If t_snd() is issued from the T_IDLE state, the provider may silently discard the data. If t_snd() is issued from any state other than T_DATAXFER , T_INREL , or T_IDLE , the provider will generate a TSYSERR with system error EPROTO (which may be reported in the manner described above).
On failure, t_errno will be set to one of the following: