Crash on Windows with core.stdc.stdlib.free()

[ketmar via Digitalmars-d-learn]

On Wed, 12 Nov 2014 14:11:35 +0000
Chris via Digitalmars-d-learn <digitalmars-d-learn at puremagic.com> wrote:

> On Wednesday, 12 November 2014 at 12:58:19 UTC, ketmar via 
> Digitalmars-d-learn wrote:
> > On Wed, 12 Nov 2014 12:40:30 +0000
> > Chris via Digitalmars-d-learn 
> > <digitalmars-d-learn at puremagic.com> wrote:
> >
> >> The following causes the DLL to crash on Windows:
> >> 
> >> Input: immutable(short)* data (immutable because in separate 
> >> thread).
> >> // Later
> >> core.stdc.stdlib.free(cast(short *)data);
> >> 
> >> (short* data is provided by the C library, where the memory is 
> >> allocated)
> >> 
> >> On Linux it works fine and never crashes, in the Windows DLL 
> >> it randomly causes an access violation in memory (both read 
> >> and write). Note that it doesn't crash immediately, it goes on 
> >> for a while, but sooner or later it crashes. If I comment out 
> >> this line, everything works fine. However, if I don't free the 
> >> memory, I'll have a memory leak. Any hints/advice/guesses?
> > seems that you are using two different allocators here. one is 
> > that
> > comes with DLL and other that comes with D. i bet they either 
> > using
> > different runtimes, or C runtime is doesn't know about another C
> > runtime in DLL.
> >
> > on GNU/Linux there is only one runtime (most of the time), so 
> > there
> > is no problem with different allocators.
> 
> That makes a lot of sense. Hm. How can I work around this problem 
> then? What's involved are a C-dll and a D-dll that uses the C-dll 
> and is loaded into a Python program. To complicate things further 
> short* data is passed to C by D. short* data is then allocated 
> and populated in C.
if you can extend C DLL, just add wrapper for `free()` there. so you
will not call `free()` from D, but call C DLL function which will free
the memory. it's a good practice anyway, 'cause it's recommended to
free memory in the same library where you allocated it.
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