The send
function is declared in the header file
`sys/socket.h'. If your flags argument is zero, you can just
as well use write
instead of send
; see section Input and Output Primitives. If the socket was connected but the connection has broken,
you get a SIGPIPE
signal for any use of send
or
write
(see section Miscellaneous Signals).
send
function is like write
, but with the additional
flags flags. The possible values of flags are described
in section Socket Data Options.
This function returns the number of bytes transmitted, or -1
on
failure. If the socket is nonblocking, then send
(like
write
) can return after sending just part of the data.
See section File Status Flags, for information about nonblocking mode.
Note, however, that a successful return value merely indicates that the message has been sent without error, not necessarily that it has been received without error.
The following errno
error conditions are defined for this function:
EBADF
EINTR
ENOTSOCK
EMSGSIZE
EWOULDBLOCK
send
blocks until the operation can be
completed.)
ENOBUFS
ENOTCONN
EPIPE
send
generates a SIGPIPE
signal first; if that
signal is ignored or blocked, or if its handler returns, then
send
fails with EPIPE
.
This function is defined as a cancellation point in multi-threaded programs, so one has to be prepared for this and make sure that allocated resources (like memory, files descriptors, semaphores or whatever) are freed even if the thread is canceled.
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