sendfile64.2 (2010 09)

s
sendfile64(2) sendfile64(2)
NAME
sendfile64() - send the contents of a Large File through a socket
SYNOPSIS
#include <sys/socket.h>
sbsize64_t sendfile64(int s, int fd, off64_t offset, bsize64_t nbytes,
const struct iovec *hdtrl, int flags);
DESCRIPTION
The sendfile64() system call transmits the contents of a file (including a Large File (greater than
2GB)) associated with the file descriptor fd, plus an optional header and trailer buffers across a socket
connection specified by s.
sendfile64()
should be used by 32-bit applications using Large Files; how-
ever, 64-bit applications can use
sendfile64() for compatibility. 64-bit applications can also use
sendfile() directly to send Large Files without special compile flags.
sendfile64() can be used
only when the socket is in a connected state.
offset specifies the offset within the file at which to start the file data transfer.
nbytes is the number of bytes to be sent from the file. If this parameter is set to zero, data from the offset
to the end of the file will be sent.
hdtrl points to a two entry
iovec structure. See write (2) for a description of the iovec
structure. The
first entry is for header information. If this pointer is non-NULL, the contents of the buffer are sent
before sending any data from the file. The second entry is for trailer information. If this pointer is non-
NULL, the contents of the buffer will be sent after the data from the file. If both pointers are NULL, or
hdtrl is a NULL pointer, only the specified range of the file will be transferred.
At the end of the call, the socket connection will be left completely open for both reading and writing,
unless the flags parameter is set to:
SF_DISCONNECT Disallow further sends and receives.
Notes
If no buffer space is available to hold the data to be transmitted,
sendfile64() blocks unless non-
blocking mode is enabled. See send(2) for a description of the nonblocking mode behavior.
Applications that compile with the
_FILE_OFFSET_BITS=64
compile flag have sendfile() system
calls converted implicitly to
sendfile64(). Also bsize_t , sbsize_t , and off_t types are implicitly con-
verted to bsize64_t , sbsize64_t , and off64_t types.
Both the
_LARGEFILE64_SOURCE
and _FILE_OFFSET_BITS=64 compile flag must be used to expli-
citly use the
sendfile64() system call. These are the recommended compile flags for both applications
using either sendfile() or sendfile64() that may want to access Large Files.
RETURN VALUE
Upon successful completion,
sendfile64() returns the number of bytes sent. This includes the header,
trailer, and the file contents. Otherwise, −1 is returned and errno is set to indicate the error.
ERRORS
If
sendfile64() fails, errno is set to one of the following values.
[EBADF] An invalid socket descriptor s,or file descriptor fd is specified.
[ENOTSOCK] s is a valid file descriptor, but it is not a socket.
[EFAULT] An invalid pointer was specified in the hdtrl parameter or the iovec structure.
[ENOBUFS] No buffer space is available in the system to perform the operation.
[EINTR] The operation was interrupted by a signal before any data was sent. (If some data
was sent,
sendfile64() returns the number of bytes sent before the signal, and
[EINTR] is not set).
[EINVAL] The offset or flags parameter is invalid.
The hdtrl parameter, or a length in the
iovec structure is invalid.
[ENOTCONN] A
sendfile64() on a socket that is not connected, or a sendfile64() on a
socket that has not completed the connect sequence with its peer, or is no longer
connected to its peer.
HP-UX 11i Version 3: September 2010 − 1 − Hewlett-Packard Company 1