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 <neon@lists.manyfish.co.uk>
           Author.

COPYRIGHT