Re: [Boost-users] Manually cleaning up TSS data in boost 1.49

Subject: Re: [Boost-users] Manually cleaning up TSS data in boost 1.49
From: Andrew Harvey (andrew.rossharvey_at_[hidden])
Date: 2012-12-05 10:25:29

On 27 November 2012 18:55, Vicente J. Botet Escriba <
vicente.botet_at_[hidden]> wrote:

>  Le 27/11/12 00:46, Andrew Harvey a écrit :
> You could always add a function that retrieves it. I don't master this
> part of Boost.Thread enough to tell you if this could be enough.
>

Hi,

In the end I didn't really want to maintain my own Boost fork, so I came up
with another solution.

The fundamental problem was that the host application, which I have no
control over, was unloading my plug-in before the thread had a chance to
call the pthread TSS destructor. When the thread did end, a jump to invalid
memory would result.

My workaround is to ensure that the plug-in's code is never actually
deallocated. I do this by finding the path of the dynamic library and
re-loading it myself. Since the library is already in memory, all this does
is increment its reference count by one. When the host application later
unloads the plug-in, the reference count is decremented but remains
non-zero.

Admittedly, it's a hack and platform-specific, but for my specific needs it
works. This may be one option for people who run into similar problems.

#include <iostream>
#include <dlfcn.h>

// Not actually read or written. Just used for the symbol
static bool beacon = false;

__attribute__((constructor))
void
initialize_dso()
{
    // Get path to this library
    Dl_info thisPlugin;
    if(dladdr(&beacon, &thisPlugin))
    {
        const char* szPluginPath = thisPlugin.dli_fname;

        // Clear error code
        dlerror();

        // Increment this library's reference count by 1
        dlopen(szPluginPath, RTLD_NOW | RTLD_LOCAL);

        const char* szErr = dlerror();
        if(szErr != NULL)
        {
            std::cerr << "Error incrementing plug-in reference count. " <<
std::endl;
        }
    }
    else
    {
        std::cerr << "Error getting plug-in info about Kaneda. " <<
std::endl;
    }
}

- Andrew