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libssh/doc/threading.dox
Aris Adamantiadis 57ef959aa3 threads: support libgcrypt 1.6 hack
Not 100% satisfied of this patch, but the way libgcrypt handles
threading in 1.6 is not compatible with custom handlers. The
new code basicaly uses pthreads in every case. This will probably
not work on windows.
2014-01-08 18:57:31 +01:00

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/**
@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 !
*/