NAME

       ne_sock_init, ne_sock_exit - perform library initialization

SYNOPSIS

       #include <ne_socket.h>

       int ne_sock_init(void);

       void ne_sock_exit(void);

DESCRIPTION

       In some platforms and configurations, neon may be using some socket or SSL libraries which require global
       initialization before use. To perform this initialization, the ne_sock_init function must be called
       before any other library functions are used.

       Once all use of neon is complete, ne_sock_exit can be called to perform de-initialization of socket or
       SSL libraries, if necessary. Uses of ne_sock_init and ne_sock_exit are "reference counted"; if N calls to
       ne_sock_init are made, only the Nth call to ne_sock_exit will have effect.

       ne_sock_init will set the disposition of the SIGPIPE signal to ignored. No change is made to the SIGPIPE
       disposition by ne_sock_exit.

       Both the SSL libraries supported by neon — OpenSSL and GnuTLS — require callbacks to be registered to
       allow thread-safe use of SSL. These callbacks are stored as global variables and so their state persists
       for as long as the library in question is loaded into the process. If multiple users of the SSL library
       exist within the process, this can be problematic, particularly if one is dynamically loaded (and may
       subsequently be unloaded).

       If neon is configured using the --enable-threadsafe-ssl flag, thread-safe SSL support will be enabled
       automatically, as covered in the following section. Otherwise, it is not safe to use neon with SSL in a
       multi-threaded process. The ne_has_support function can be used to determine whether neon is built to
       enable thread-safety support in the SSL library.

   Thread-safe SSL with OpenSSL
       neon follows two simple rules when dealing with the OpenSSL locking callbacks:

       •   ne_sock_init will set thread-safety locking callbacks if and only if no locking callbacks are already
           registered.

       •   ne_sock_exit will unset the thread-safety locking callbacks if and only if the locking callbacks
           registered are those registered by ne_sock_init.

       Applications and libraries should be able to co-operate to ensure that SSL use is always thread-safe if
       similar rules are always followed.

   Thread-safe SSL with GnuTLS
       The cryptography library used by GnuTLS, libgcrypt, only supports an initialization operation to register
       thread-safety callbacks.  ne_sock_init will register the thread-safe locking callbacks on first use;
       ne_sock_exit cannot unregister them. If multiple users of GnuTLS are present within the process, it is
       unsafe to dynamically unload neon from the process if neon is configured with thread-safe SSL support
       enabled (since the callbacks would be left pointing at unmapped memory once neon is unloaded).

RETURN VALUE

       ne_sock_init returns zero on success, or non-zero on error. If an error occurs, no further use of the
       neon library should be attempted.

SEE ALSO

       neon(3), ne_has_support(3)

AUTHOR

       Joe Orton
           Author.

COPYRIGHT