mirror of
https://github.com/libssh2/libssh2.git
synced 2025-10-24 14:53:03 +03:00
b889b39945
To render in Git webviews as-is, to make it easier to edit, verify,
and to sync up with curl.
- add options to not build the `.3` man pages:
- autotools: `--disable-docs`
- cmake: `LIBSSH2_BUILD_DOCS=OFF`
- building `.3` man pages requires Perl after this patch.
- drop `mansyntax` and the shell / `grep` / GNU `man` tool requirements with it.
- scripts and most logic were copied from curl.
- add `cd2nroff` from curl, with edits to relax curl-specific checks.
- used `nroff2cd` (from curl) to convert from `.3` to `.md`. Then
manually fixed copyrights, inline function references and a couple
of other things.
Credits-to: Daniel Stenberg
Ref: eefcc1bda4
Ref: https://github.com/curl/curl/pull/12730
Ref: https://github.com/libssh2/www/issues/25#issuecomment-3289431671
Closes #1660
90 lines
3.0 KiB
Markdown
90 lines
3.0 KiB
Markdown
---
|
|
c: Copyright (C) The libssh2 project and its contributors.
|
|
SPDX-License-Identifier: BSD-3-Clause
|
|
Title: libssh2_sftp_write
|
|
Section: 3
|
|
Source: libssh2
|
|
See-also:
|
|
- libssh2_sftp_open_ex(3)
|
|
---
|
|
|
|
# NAME
|
|
|
|
libssh2_sftp_write - write SFTP data
|
|
|
|
# SYNOPSIS
|
|
|
|
~~~c
|
|
#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 is not 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 have once called libssh2_sftp_write() with data and it returns
|
|
short, you MUST still assume that the rest of the data might have been cached so
|
|
you need to make sure you do not 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 is not
|
|
really a failure per se.
|
|
|
|
If this function returns 0 (zero) it should not be considered an error, but
|
|
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.
|