'\" te
.\" Copyright (c) 2009, Sun Microsystems, Inc. All Rights Reserved.
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License.
.\" You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.  See the License for the specific language governing permissions and limitations under the License.
.\" When distributing Covered Code, include this CDDL HEADER in each file and include the License file at usr/src/OPENSOLARIS.LICENSE.  If applicable, add the following below this CDDL HEADER, with the fields enclosed by brackets "[]" replaced with your own identifying information: Portions Copyright [yyyy] [name of copyright owner]
.\" Copyright 2022 Garrett D'Amore
.TH SENDFILEV 3EXT "July 3, 2022"
.SH NAME
sendfilev \- send a file
.SH SYNOPSIS
.nf
\fBcc\fR [ \fIflag\fR\&.\|.\|. ] \fIfile\fR\&.\|.\|. \fB-lsendfile\fR  [ \fIlibrary\fR... ]
#include <sys/sendfile.h>

\fBssize_t\fR \fBsendfilev\fR(\fBint\fR \fIfildes\fR, \fBconst struct sendfilevec *\fR\fIvec\fR,
     \fBint\fR \fIsfvcnt\fR, \fBsize_t *\fR\fIxferred\fR);
.fi

.SH PARAMETERS
The \fBsendfilev()\fR function supports the following parameters:
.sp
.ne 2
.na
\fB\fIfildes\fR\fR
.ad
.RS 11n
A file descriptor to a regular file or to a \fBAF_INET\fR or
\fBAF_INET6\fR family type \fBSOCK_STREAM\fR socket that is open for writing.
.RE

.sp
.ne 2
.na
\fB\fIvec\fR\fR
.ad
.RS 11n
An array of \fBSENDFILEVEC_T\fR, as defined in the \fBsendfilevec\fR structure
below.
.RE

.sp
.ne 2
.na
\fB\fIsfvcnt\fR\fR
.ad
.RS 11n
The number of members in \fIvec\fR.
.RE

.sp
.ne 2
.na
\fB\fIxferred\fR\fR
.ad
.RS 11n
The total number of bytes written to \fBout_fd\fR.
.RE

.SH DESCRIPTION
The \fBsendfilev()\fR function attempts to write data from the \fIsfvcnt\fR
buffers specified by the members of \fIvec\fR array: \fBvec[0], vec[1], ... ,
vec[sfvcnt-1]\fR. The \fIfildes\fR argument is a file descriptor to a regular
file or to an \fBAF_INET\fR or \fBAF_INET6\fR family type
\fBSOCK_STREAM\fR socket that is open for writing.
.sp
.LP
This function is analogous to \fBwritev\fR(2), but can read from both buffers
and file descriptors. Unlike \fBwritev()\fR, in the case of multiple writers to
a file the effect of \fBsendfilev()\fR is not necessarily atomic; the writes
may be interleaved. Application-specific synchronization methods must be
employed if this causes problems.
.sp
.LP
The following is the \fBsendfilevec\fR structure:
.sp
.in +2
.nf
typedef struct sendfilevec {
        int     sfv_fd;         /* input fd */
        uint_t  sfv_flag;       /* Flags. see below */
        off_t   sfv_off;        /* offset to start reading from */
        size_t  sfv_len;        /* amount of data */
} sendfilevec_t;

#define SFV_FD_SELF     (-2)
.fi
.in -2

.sp
.LP
To send a file, open the file for reading and point \fBsfv_fd\fR to the file
descriptor returned as a result. See \fBopen\fR(2). \fBsfv_off\fR should
contain the offset within the file. \fBsfv_len\fR should have the length of the
file to be transferred.
.sp
.LP
The \fIxferred\fR argument is updated to record the total number of bytes
written to \fBout_fd\fR.
.sp
.LP
The \fBsfv_flag\fR field is reserved and should be set to zero.
.sp
.LP
To send data directly from the address space of the process, set \fBsfv_fd\fR
to \fBSFV_FD_SELF\fR. \fBsfv_off\fR should point to the data, with
\fBsfv_len\fR containing the length of the buffer.
.SH RETURN VALUES
Upon successful completion, the \fBsendfilev()\fR function returns total number
of bytes written to \fBout_fd\fR. Otherwise, it returns \fB-1\fR, and
\fBerrno\fR is set to indicate the error. The \fIxferred\fR argument contains
the amount of data successfully transferred, which can be used to discover the
error vector.
.SH ERRORS
.ne 2
.na
\fB\fBEACCES\fR\fR
.ad
.RS 16n
The process does not have appropriate privileges or one of the files pointed by
\fBsfv_fd\fR does not  have appropriate permissions.
.RE

.sp
.ne 2
.na
\fB\fBEAFNOSUPPORT\fR\fR
.ad
.RS 16n
The implementation does not support the specified address family for socket.
.RE

.sp
.ne 2
.na
\fB\fBEAGAIN\fR\fR
.ad
.RS 16n
Mandatory file or record locking is set on either the file descriptor or output
file descriptor if it points at regular files. \fBO_NDELAY\fR or
\fBO_NONBLOCK\fR is set, and there is a blocking record lock. An attempt has
been made to write to a stream that cannot accept data with the \fBO_NDELAY\fR
or the \fBO_NONBLOCK\fR flag set.
.RE

.sp
.ne 2
.na
\fB\fBEBADF\fR\fR
.ad
.RS 16n
The \fIfildes\fR argument is not a valid descriptor open for writing or an
\fBsfv_fd\fR is invalid or not open for reading.
.RE

.sp
.ne 2
.na
\fB\fBEFAULT\fR\fR
.ad
.RS 16n
The \fIvec\fR argument points to an illegal address.
.sp
The \fIxferred\fR argument points to an illegal address.
.RE

.sp
.ne 2
.na
\fB\fBEINTR\fR\fR
.ad
.RS 16n
A signal was caught during the write operation and no data was transferred.
.RE

.sp
.ne 2
.na
\fB\fBEINVAL\fR\fR
.ad
.RS 16n
The \fIsfvcnt\fR argument was less than or equal to \fB0\fR. One of the
\fBsfv_len\fR values in \fIvec\fR array was less than or equal to \fB0\fR, or
greater than the file size. An \fBsfv_fd\fR is not seekable.
.sp
Fewer bytes were transferred than were requested.
.RE

.sp
.ne 2
.na
\fB\fBEIO\fR\fR
.ad
.RS 16n
An I/O error occurred while accessing the file system.
.RE

.sp
.ne 2
.na
\fB\fBEPIPE\fR\fR
.ad
.RS 16n
The \fIfildes\fR argument is a socket that has been shut down for writing.
The \fBSIGPIPE\fR signal is generated to the calling thread.
The process dies unless special provisions were taken to catch or ignore
the signal.
.RE

.sp
.ne 2
.na
\fB\fBEPROTOTYPE\fR\fR
.ad
.RS 16n
The socket type is not supported.
.RE

.SH USAGE
The \fBsendfilev()\fR function has a transitional interface for 64-bit file
offsets. See \fBlf64\fR(7).
.SH EXAMPLES
The following example sends 2 vectors, one of HEADER data and a file of length
100 over \fBsockfd\fR. \fBsockfd\fR is in a connected state, that is,
\fBsocket()\fR, \fBaccept()\fR, and \fBbind()\fR operation are complete.
.sp
.in +2
.nf
#include <sys/sendfile.h>
\&.
\&.
\&.
int
main (int argc, char *argv[]){
  int sockfd;
  ssize_t ret;
  size_t xfer;
  struct sendfilevec vec[2];
    .
    .
    .
  vec[0].sfv_fd = SFV_FD_SELF;
  vec[0].sfv_flag = 0;
  vec[0].sfv_off = "HEADER_DATA";
  vec[0].sfv_len = strlen("HEADER_DATA");
  vec[1].sfv_fd = open("input_file",.... );
  vec[1].sfv_flag = 0;
  vec[1].sfv_off = 0;
  vec[1].sfv_len = 100;

  ret = sendfilev(sockfd, vec, 2, &xfer);
\&.
\&.
\&.
}
.fi
.in -2

.SH ATTRIBUTES
See \fBattributes\fR(7) for descriptions of the following attributes:
.sp

.sp
.TS
box;
c | c
l | l .
ATTRIBUTE TYPE	ATTRIBUTE VALUE
_
Interface Stability	Committed
_
MT-Level	MT-Safe
.TE

.SH SEE ALSO
.BR open (2),
.BR writev (2),
.BR sendfile (3EXT),
.BR libsendfile (3LIB),
.BR socket (3SOCKET),
.BR attributes (7)