pthread_key_create destructor

pthread_key_create destructor

[Thomas Beckmann]

Hi,

I have a problem with pthread_key_create ().
I'm using the latest(2002-11-4) pre-build pthreadVC.dll on Windows XP with 
MSVC++ 6.0.
I wrote the following example to explain the problem:

#include <pthread.h>
#include <windows.h>
#include <stdio.h>

pthread_key_t key;

void destructor (void *ptr)
{
	printf ((char*)ptr);
	free (ptr);
}

int main (int argc, char *argv[])
{
	char *ptr;

	pthread_key_create (&key, &destructor);
	if ((ptr = pthread_getspecific(key)) == NULL) {
		ptr = strdup ("test\n");
		pthread_setspecific (key, ptr);
	}
	return 0;
}

I think, this is a valid example, and it works fine as a release version 
but the debug version crashes inside the destructor() function .
The address of ptr inside destructor() is the same as inside main() but 
when having a look at the memory pointed to by ptr, it is initialized to 
zero at the end of main but unspecified inside of destructor().
It seems, that the address of ptr is already outside the applications 
address space or somehow else invalid, so the destructor is called too late.


Thanks for any help,

Thomas Beckmann

RE: pthread_key_create destructor

[Bossom, John]

Note:

You need to call pthread_exit() in your example... you should
be able to find documentation in several books that indicate
that you need to do this to ensure the key destructors are
called on the main thread of execution
(i.e. this is not a pthread-win32 specific thing)

Cheers,
John

-----Original Message-----
From: beckmann.bremen@t-online.de [mailto:beckmann.bremen@t-online.de]
Sent: Friday, January 03, 2003 10:30 AM
To: pthreads-win32@sources.redhat.com
Subject: pthread_key_create destructor


Hi,

I have a problem with pthread_key_create ().
I'm using the latest(2002-11-4) pre-build pthreadVC.dll on Windows XP with 
MSVC++ 6.0.
I wrote the following example to explain the problem:

#include <pthread.h>
#include <windows.h>
#include <stdio.h>

pthread_key_t key;

void destructor (void *ptr)
{
	printf ((char*)ptr);
	free (ptr);
}

int main (int argc, char *argv[])
{
	char *ptr;

	pthread_key_create (&key, &destructor);
	if ((ptr = pthread_getspecific(key)) == NULL) {
		ptr = strdup ("test\n");
		pthread_setspecific (key, ptr);
	}
	return 0;
}

I think, this is a valid example, and it works fine as a release version 
but the debug version crashes inside the destructor() function .
The address of ptr inside destructor() is the same as inside main() but 
when having a look at the memory pointed to by ptr, it is initialized to 
zero at the end of main but unspecified inside of destructor().
It seems, that the address of ptr is already outside the applications 
address space or somehow else invalid, so the destructor is called too late.


Thanks for any help,

Thomas Beckmann

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