NAME

       libssh2_sftp_write - write SFTP data

SYNOPSIS

       #include <libssh2.h>
       #include <libssh2_sftp.h>

       ssize_t libssh2_sftp_write(LIBSSH2_SFTP_HANDLE *handle,
                                  const char *buffer,
                                  size_t count);

DESCRIPTION

       libssh2_sftp_write(3)  writes  a block of data to the SFTP server. This method is modeled after the POSIX
       write() function and uses the same calling semantics.

       handle - SFTP file handle as returned by libssh2_sftp_open_ex(3).

       buffer - points to the data to send off.

       count - Number of bytes from 'buffer' to write. Note that it may not be possible to write  all  bytes  as
       requested.

       libssh2_sftp_handle(3)  will use as much as possible of the buffer and put it into a single SFTP protocol
       packet. This means that to get maximum performance when sending larger files, you should  try  to  always
       pass in at least 32K of data to this function.

WRITE AHEAD

       Starting  in libssh2 version 1.2.8, the default behavior of libssh2 is to create several smaller outgoing
       packets for all data you pass to this function and it will return a positive number as soon as the  first
       packet is acknowledged from the server.

       This  has  the  effect  that sometimes more data has been sent off but isn't acked yet when this function
       returns, and when this function is subsequently called again to write more data, libssh2 will immediately
       figure out that the data is already received remotely.

       In most normal situation this should not cause any problems, but it should be noted that if  you've  once
       called  libssh2_sftp_write()  with  data and it returns short, you MUST still assume that the rest of the
       data might've been cached so you need to make sure you don't alter that data and think that  the  version
       you have in your next function invoke will be detected or used.

       The  reason  for  this  funny behavior is that SFTP can only send 32K data in each packet and it gets all
       packets acked individually. This means we cannot use a simple serial approach if we want  to  reach  high
       performance even on high latency connections. And we want that.

RETURN VALUE

       Actual number of bytes written or negative on failure.

       If  used  in  non-blocking  mode,  it  returns  LIBSSH2_ERROR_EAGAIN when it would otherwise block. While
       LIBSSH2_ERROR_EAGAIN is a negative number, it isn't really a failure per se.

       If this function returns 0 (zero) it should not be considered an error, but  simply  that  there  was  no
       error but yet no payload data got sent to the other end.

ERRORS

       LIBSSH2_ERROR_ALLOC -  An internal memory allocation call failed.

       LIBSSH2_ERROR_SOCKET_SEND - Unable to send data on socket.

       LIBSSH2_ERROR_SOCKET_TIMEOUT -

       LIBSSH2_ERROR_SFTP_PROTOCOL  -  An  invalid SFTP protocol response was received on the socket, or an SFTP
       operation caused an errorcode to be returned by the server.

SEE ALSO

       libssh2_sftp_open_ex(3)

libssh2 0.15                                       1 Jun 2007                              libssh2_sftp_write(3)