[libvirt] [PATCH] Make virInitialize thread safe

[Daniel P. Berrange]

On Wed, Oct 10, 2012 at 05:32:21PM +0200, Matthias Bolte wrote:
> 2012/10/10 Daniel P. Berrange <berrange at redhat.com>:
> > From: "Daniel P. Berrange" <berrange at redhat.com>
> >
> > Currently there is a restriction that multi-threaded applications
> > must manually call virInitialize, before threads start using
> > libvirt, because it is not thread-safe. By switching it to use
> > a virOnceControl initializer we gain thread safety, and thus
> > applications no longer need to manually call it. They can rely
> > on virConnectOpen invoking it for them.
> >
> > Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
> > ---
> >  src/libvirt.c | 139 ++++++++++++++++++++++++++++++----------------------------
> >  1 file changed, 71 insertions(+), 68 deletions(-)
> 
> > +/**
> > + * virInitialize:
> > + *
> > + * Initialize the library.
> > + *
> > + * This method is invoked automatically by any of the virConnectOpen API
> > + * calls. Since release 1.0.0, there is no need to call this method even
> > + * in a multithreaded application, since initialization is performed in
> > + * a thread safe manner.
> 
> Are you really sure that this is true? What about the calls
> gcry_control and curl_global_init?

There's no issue with that. We are still ensuring that virInitialize is
the first thing invoked in libvirt. We are simply doing that automatically
now, instead of requiring client apps todo it.

> 
> > + * The only time it would be neccessary to call virInitialize is if the
> > + * application did not invoke virConnectOpen as its first API call.
> > + *
> > + * Returns 0 in case of success, -1 in case of error
> > + */

Daniel
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