Re: RFC: dsound: Add support for enumerating capture devices through openal, try 4

[Ken Thomases]

On Dec 2, 2009, at 12:11 PM, Maarten Lankhorst wrote:
> This patch doesn't apply, just a rfc email to see if this approach  
> is correct :)
> +static void *openal_handle = RTLD_DEFAULT;
> +#ifdef SONAME_LIBOPENAL
> +    char error[128];
> +    openal_handle = wine_dlopen(SONAME_LIBOPENAL, RTLD_NOW, error,  
> sizeof(error));
> +    if (!openal_handle)
> +        ERR("Couldn't load " SONAME_LIBOPENAL ": %s\n", error);
> +#endif
> +#define LOAD_FUNCPTR(f) \
> +    if((p##f = wine_dlsym(openal_handle, #f, NULL, 0)) == NULL) { \
> +        ERR("Couldn't lookup %s in libopenal\n", #f); \
> +        failed = 1; \
> +    }
> +
> +    LOAD_FUNCPTR(alcCreateContext);

By defaulting to RTLD_DEFAULT on the Mac (where SONAME_LIBOPENAL won't  
be defined), is there any risk that wine_dlsym will find the symbols  
from Wine's openal32.dll.so rather than the linked OpenAL framework?   
If it does, is that a problem?

I had proposed using RTLD_NEXT for the default to avoid that  
possibility, although it seems that RTLD_NEXT isn't universally  
available.  We might use RTLD_NEXT if it's defined and RTLD_DEFAULT  
otherwise.

-Ken

RFC: dsound: Add support for enumerating capture devices through openal, try 4

[Maarten Lankhorst]

Hi Ken,

Ken Thomases schreef:
> On Dec 2, 2009, at 12:11 PM, Maarten Lankhorst wrote:
> > This patch doesn't apply, just a rfc email to see if this approach is 
> > correct :)
> > +static void *openal_handle = RTLD_DEFAULT;
> > +#ifdef SONAME_LIBOPENAL
> > +    char error[128];
> > +    openal_handle = wine_dlopen(SONAME_LIBOPENAL, RTLD_NOW, error, 
> > sizeof(error));
> > +    if (!openal_handle)
> > +        ERR("Couldn't load " SONAME_LIBOPENAL ": %s\n", error);
> > +#endif
> > +#define LOAD_FUNCPTR(f) \
> > +    if((p##f = wine_dlsym(openal_handle, #f, NULL, 0)) == NULL) { \
> > +        ERR("Couldn't lookup %s in libopenal\n", #f); \
> > +        failed = 1; \
> > +    }
> > +
> > +    LOAD_FUNCPTR(alcCreateContext);
>
> By defaulting to RTLD_DEFAULT on the Mac (where SONAME_LIBOPENAL won't 
> be defined), is there any risk that wine_dlsym will find the symbols 
> from Wine's openal32.dll.so rather than the linked OpenAL framework?  
> If it does, is that a problem?
>
> I had proposed using RTLD_NEXT for the default to avoid that 
> possibility, although it seems that RTLD_NEXT isn't universally 
> available.  We might use RTLD_NEXT if it's defined and RTLD_DEFAULT 
> otherwise.
> Those symbols are prefixed with wine_ and libopenal is static linked to 
> openal32, so there cannot be duplicate names between the 2. We don't 
> have to worry about the win32 symbol names, since they're not handled by 
> wine_dlsym. Just to be sure I tested, and confirmed that.

Cheers,
Maarten.