Date: Wed, 28 May 2003 20:34:16 -0400 From: Craig Rodrigues <rodrigc@attbi.com> To: freebsd-threads@freebsd.org Subject: Re: Question about OpenSSL id_function() and pthreads Message-ID: <20030529003416.GA3712@attbi.com> In-Reply-To: <Pine.GSO.4.10.10305282000170.133-100000@pcnet5.pcnet.com> References: <20030528235120.GA3481@attbi.com> <Pine.GSO.4.10.10305282000170.133-100000@pcnet5.pcnet.com>
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On Wed, May 28, 2003 at 08:07:24PM -0400, Daniel Eischen wrote:
> > I have some third party C++ code which tries to implements this function:
> >
> > static unsigned long
> > idFunction()
> > {
> > #ifdef _WIN32
> > return static_cast<unsigned long>(GetCurrentThreadId());
> > #else
> > return static_cast<unsigned long>(pthread_self());
> > #endif
> > }
> >
> >
> > This code does not compile on FreeBSD-CURRENT:
> >
> > OpenSSLPluginI.cpp: In function `long unsigned int idFunction()':
> > OpenSSLPluginI.cpp:151: invalid static_cast from type `pthread*' to type `long
> > unsigned int'
>
> I don't know C++ well (much at all). What does static_cast do?
static_cast, unlike C style casts, have restrictions which can
result in compile-time errors.
The full definition of static_cast is here:
http://www.csci.csusb.edu/dick/c++std/cd2/expr.html#expr.static.cast
A static_cast *cannot* convert a pointer type to an integral type
(unsigned long), and will result in a compile time error.
> The error message makes it look as if you are converting
> a "pthread" * to "long unsigned int". Don't you just
> want "unsigned long" instead?
This function needs to return a unique numeric identifier
based on a thread. pthread_self() returns a type of pthread_t.
On Linux (where this code was written), pthread_t is:
typedef unsigned long int pthread_t;
So that is why this 3rd party code compiles and works fine on Linux.
Obviously, this is not true on FreeBSD. The fact that
this code relies on pthread_t being an integer type is bogus,
but that's what you get for using 3rd party code. :)
So how do I solve this problem on FreeBSD?
--
Craig Rodrigues
http://home.attbi.com/~rodrigc
rodrigc@attbi.com
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