niceSOFT/libssh | Gitverse

doc/threading.dox
66 строк2 KB
Aris Adamantiadis
threads: support libgcrypt 1.6 hack
08 янв 2014, 21:57
08 янв 2014, 21:5757ef959
/**
@page libssh_tutor_threads Chapter 8: Threads with libssh
@section threads_with_libssh How to use libssh with threads

libssh may be used in multithreaded applications, but under several conditions :
 - Threading must be initialized during the initialization of libssh. This 
   initialization must be done outside of any threading context.
 - If pthreads is being used by your application (or your framework's backend),
   you must link with libssh_threads dynamic library and initialize 
   threading with the ssh_threads_pthreads threading object.
 - If an other threading library is being used by your application, you must 
   implement all the methods of the ssh_threads_callbacks_struct structure
   and initialize libssh with it.
 - At all times, you may use different sessions inside threads, make parallel
   connections, read/write on different sessions and so on. You *cannot* use a
   single session (or channels for a single session) in several threads at the same 
   time. This will most likely lead to internal state corruption. This limitation is
   being worked out and will maybe disappear later.
   
@subsection threads_init Initialization of threads

To initialize threading, you must first select the threading model you want to
use, using ssh_threads_set_callbacks(), then call ssh_init().

@code 
#include <libssh/callbacks.h>
...
ssh_threads_set_callbacks(ssh_threads_get_noop());
ssh_init();
@endcode

ssh_threads_noop is the threading structure that does nothing. It's the
threading callbacks being used by default when you're not using threading.

@subsection threads_pthread Using libpthread with libssh

If your application is using libpthread, you may simply use the libpthread
threading backend:

@code
#include <libssh/callbacks.h>
...
ssh_threads_set_callbacks(ssh_threads_get_pthread());
ssh_init();
@endcode

However, you must be sure to link with the library ssh_threads. If 
you're using gcc, you must use the commandline
@code
gcc -o output input.c -lssh -lssh_threads
@endcode 


@subsection threads_other Using another threading library

You must find your way in the ssh_threads_callbacks_struct structure. You must
implement the following methods :
- mutex_lock
- mutex_unlock
- mutex_init
- mutex_destroy
- thread_id

libgcrypt 1.6 and bigger backend does not support custom callback. Using anything else than pthreads (ssh_threads_get_pthread()) here will fail.
Good luck !
*/