in reply to Re^3: XS: free() outside of the main thread causes crash on Windows
in thread XS: free() outside of the main thread causes crash on Windows

It says that free() is win32_free() and malloc() is win32_malloc().
  • Comment on Re^4: XS: free() outside of the main thread causes crash on Windows

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Re^5: XS: free() outside of the main thread causes crash on Windows
by BrowserUk (Patriarch) on Sep 25, 2014 at 08:32 UTC

    If you look into win32.c/.h and unwind those functions, you'll find that they use a custom (pseudo-C++ style) allocator that uses different pools for different threads. (iThreads, that is.)

    But for that to work properly, it needs to be initialised and as you are not instantiating an interpreter in your thread(s), you are not getting that initialisation done.

    Basically, by using the perl environment to compile (what is essentially) pure C code, you're just opening yourself to a whole world of hurt. It, the Perl environment, simply isn't designed to be used that way.

    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".
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[reply]
Re^5: XS: free() outside of the main thread causes crash on Windows
by Anonymous Monk on Sep 25, 2014 at 08:07 UTC
    If you do this on win32 I don't get this "double free" error 
    #include <pthread.h>

void *thread(void *arg) {
    char *msg = (char*)arg;
    printf("thread: %s\n", msg);
    free(msg);
    return NULL;
}

#include "EXTERN.h"
...

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      I changed it to
      #include <pthread.h>

void *thread(void *arg) {
    char *msg = (char*)arg;
    printf("thread: %s\n", msg);
    free(msg);
    return NULL;
}

#include "EXTERN.h"
#include "perl.h"
#include "XSUB.h"
#include "ppport.h"

MODULE = My    PACKAGE = My

void
test_thread(char *msg)
    PPCODE:
        char *thread_arg = malloc((strlen(msg)+1)*sizeof(char));
        strcpy(thread_arg, msg);
        pthread_t tid;
        pthread_create(&tid, NULL, thread, (void*)thread_arg);
        
        void *rv;
        pthread_join(tid, &rv);

      [download]

      And the problem still here: crash on each run
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        And the problem still here: crash on each run

        No problem for me I got citrusperl 5.16.1 with 

        $ gcc --version
gcc (gcc-4.6.3 release with patches [build 20121012 by perlmingw.sf.ne
+t]) 4.6.3
Copyright (C) 2011 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There i
+s NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PUR
+POSE.

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      And gdb output looks not very usefull
      (gdb) r t.pl
Starting program: C:\Perl64\bin\perl.exe t.pl
[New Thread 17748.0x6114]
[New Thread 17748.0x61f8]
thread: Just another XS hacker
warning: Critical error detected c0000374


Program received signal SIGTRAP, Trace/breakpoint trap.
[Switching to Thread 17748.0x61f8]
0x00000000770d40d0 in ntdll!RtlUnhandledExceptionFilter ()
   from C:\WINDOWS\SYSTEM32\ntdll.dll
(gdb) bt
#0  0x00000000770d40d0 in ntdll!RtlUnhandledExceptionFilter ()
   from C:\WINDOWS\SYSTEM32\ntdll.dll
#1  0x00000000770d4746 in ntdll!EtwEnumerateProcessRegGuids ()
   from C:\WINDOWS\SYSTEM32\ntdll.dll
#2  0x00000000770d5952 in ntdll!RtlQueryProcessLockInformation ()
   from C:\WINDOWS\SYSTEM32\ntdll.dll
#3  0x00000000770d7604 in ntdll!RtlLogStackBackTrace ()
   from C:\WINDOWS\SYSTEM32\ntdll.dll
#4  0x000000007707dc47 in ntdll!RtlIsDosDeviceName_U ()
   from C:\WINDOWS\SYSTEM32\ntdll.dll
Backtrace stopped: previous frame inner to this frame (corrupt stack?)
(gdb)

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[reply]
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