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)