in reply to Re^8: XS: free() outside of the main thread causes crash on Windows
in thread XS: free() outside of the main thread causes crash on Windows

Yes, this makes the trick. After changing source code to
#include <pthread.h> #include "EXTERN.h" #include "perl.h" #include "XSUB.h" #include "ppport.h" #undef free #undef malloc

You'll get away with that as long as you do not attempt to pass anything you malloc() to perl.

When it gets interesting is when you try to free() something allocated by Perl within your C/XS code; or vice versa.

As I mentioned above, under iThreads, different pools of memory are used for each (perl instantiated) thread via the custom allocator.

Attempt free something allocated by the CRT (ie. by you in your XS code with #undef malloc) and then free it using the custom allocators free() (eg. by passing it into Perl and then letting it go out of scope) and you'll probably get the infamous: "free to wrong pool" message.

Attempt to free something allocated by that allocator using the CRT free() and you'll blow up bigtime.


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Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
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Re^10: XS: free() outside of the main thread causes crash on Windows
by OlegG (Monk) on Sep 25, 2014 at 10:14 UTC
    I understand that. And in my real code i'll undef this temporarily and only to manipulate pure C structures.
      And in my real code i'll undef this temporarily and only to manipulate pure C structures.

      The way I did it was to put crt(re|C|M)alloc() & crtFree() functions in a separate file with the appropriate #undefs.


      With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
      Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
      "Science is about questioning the status quo. Questioning authority".
      In the absence of evidence, opinion is indistinguishable from prejudice.