.TH socket_sendfile 3
.SH NAME
socket_sendfile \- send a file over a TCP socket
.SH SYNTAX
.B #include <socket.h>

int \fBsocket_sendfile\fP(int \fIout\fR, int \fIin\fR, uint32 \fIoffset\fR,
                    uint32 \fIbytes\fR);
.SH DESCRIPTION
socket_sendfile sends \fIbytes\fR bytes starting at \fIoffset\fR in the
file \fIin\fR to the socket connected to file descriptor \fIout\fR.

The socket must be connected.

Note that the underlying sendfile system call is system specific and
currently only implemented on Linux.  On other operating systems, it is
emulated with a read/write loop.
.SH RETURN VALUE
socket_sendfile returns 0 if the data was sent successfully.  If not,
it returns -1 and sets errno appropriately.
.SH EXAMPLE
  #include <socket.h>
  #include <open.h>

  int \fIs\fR;
  char \fIip\fR[4];
  uint16 \fIp\fR;
  int \fIfd\fR = open_read("/etc/passwd");

  \fIs\fR = socket_tcp();
  socket_connect4(s,ip,p);
  socket_sendfile(s,fd,0,23);

.SH "SEE ALSO"
socket_send6(3)