buffer is a pointer to a pre-allocated buffer of at least
buffer_maxlen bytes to read data into.
Reads a block of data from an LIBSSH2_SFTP_HANDLE. This method is modelled
after the POSIX
read(2)
function and uses the same calling semantics.
libssh2_sftp_read(3)
will attempt to read as much as possible however it may not fill all of buffer
if the file pointer reaches the end or if further reads would cause the socket
to block.
RETURN VALUE
Number of bytes actually populated into buffer, or negative on failure.
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.
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.