libssh2_channel_open_ex(3)

💖 libssh2_channel_open_ex(3) — the libssh2 girlies' guide 💖

okay so bestie, welcome to the manual page for libssh2_channel_open_ex — the function that opens a channel, and yes she's the moment. this lives in libssh2, and it's lowkey the main character of the whole session-channel situation. sit down, hydrate, let's go 🫶

✨ NAME ✨

libssh2_channel_open_ex — establish a generic session channel 💅

✨ SYNOPSIS ✨

#include <libssh2.h>

LIBSSH2_CHANNEL *
libssh2_channel_open_ex(LIBSSH2_SESSION *session, const char *channel_type,
                        unsigned int channel_type_len,
                        unsigned int window_size,
                        unsigned int packet_size,
                        const char *message, unsigned int message_len);

LIBSSH2_CHANNEL *
libssh2_channel_open_session(session);

✨ DESCRIPTION ✨

okay so here's the tea on every single argument, no skips, no skimming, fr fr:

• session — the session instance, as returned by libssh2_session_init_ex(3). it's literally your whole connection, your girl 🎀
• channel_type — the channel type you wanna open. typically one of session, direct-tcpip, or tcpip-forward. the SSH2 protocol allowed for additional types including local and custom channel types, so yeah, there's range 👑
• channel_type_len — the length of channel_type. just count her. 💀
• window_size — the maximum amount of unacknowledged data the remote host is allowed to send before it receives an SSH_MSG_CHANNEL_WINDOW_ADJUST packet. think of it as her patience meter 🌸
• packet_size — the maximum number of bytes the remote host is allowed to send in a single SSH_MSG_CHANNEL_DATA or SSG_MSG_CHANNEL_EXTENDED_DATA packet. yes that second one really says SSG_MSG_CHANNEL_EXTENDED_DATA in the original, i do not make the rules, i just transcribe them 💀
• message — extra data, as required by whichever channel_type you picked. it's giving "bring your own payload" ✨
• message_len — the length of the message parameter. again: count her. 🍓

so what does she actually do? she allocates a new channel for exchanging data with the server, that's the whole vibe 🦋

and like, technically you can call her directly, but bestie, she's typically called through her macroized form: libssh2_channel_open_session(3), or via libssh2_channel_direct_tcpip(3), or libssh2_channel_forward_listen(3). the macros are the girlies that show up to the party so you don't have to do the long-form homework 🌈

✨ RETURN VALUE ✨

she hands you back a pointer to a newly allocated LIBSSH2_CHANNEL instance. that's your new baby, your icon, your channel 💖

or... NULL on errors. and if you get NULL, we're not okay, we're checking ERRORS below. 😭

✨ ERRORS ✨

the glow-downs, in order:

• LIBSSH2_ERROR_ALLOC — an internal memory allocation call failed. malloc said "not today" 💀
• LIBSSH2_ERROR_SOCKET_SEND — unable to send data on socket. the socket is ghosting you 👻
• LIBSSH2_ERROR_CHANNEL_FAILURE — (the original leaves this one blank, so we're just gonna hold space for her 🕯️)
• LIBSSH2_ERROR_EAGAIN — marked for non-blocking I/O but the call would block. she's busy, try again later, she'll text back 🙈

✨ SEE ALSO ✨

Add related functions

and that's the whole page, bestie!! 🎀 no cap, you now know libssh2_channel_open_ex better than most people know their own wifi password.

sign-off szn: this page is from libssh2 version 0.15, dated 1 Jun 2007. she's an icon, she's a legend, she's the moment, and she has been since 2007. periodt. 💅✨👑