pthread와 valgrind에서의 memory leak

#include <stdio.h>
#include <pthread.h>
 
void *thread_routine(void *arg)
{
	return arg;
}
 
int main()
{
	int ret;
	void *result;
	pthread_t ThreadID;
 
	ret = pthread_create(&ThreadID, NULL, thread_routine, NULL);
	if( ret != 0 )
	{
		printf("create thread fail\n");
		return 0;
	}
 
	ret = pthread_join(ThreadID, &result);
	if( ret != 0 )
	{
		printf("pthread_join error\n");
		return 0;
	}
 
	return 0;
}

==7480== Memcheck, a memory error detector.
==7480== Copyright (C) 2002-2005, and GNU GPL'd, by Julian Seward et al.
==7480== Using LibVEX rev 1471, a library for dynamic binary translation.
==7480== Copyright (C) 2004-2005, and GNU GPL'd, by OpenWorks LLP.
==7480== Using valgrind-3.1.0-Debian, a dynamic binary instrumentation framework.
==7480== Copyright (C) 2000-2005, and GNU GPL'd, by Julian Seward et al.
==7480== For more details, rerun with: -v
==7480==
==7480==
==7480== ERROR SUMMARY: 0 errors from 0 contexts (suppressed: 13 from 1)
==7480== malloc/free: in use at exit: 68 bytes in 1 blocks.
==7480== malloc/free: 1 allocs, 0 frees, 68 bytes allocated.
==7480== For counts of detected errors, rerun with: -v
==7480== searching for pointers to 1 not-freed blocks.
==7480== checked 8,480,624 bytes.
==7480==
==7480== LEAK SUMMARY:
==7480==    definitely lost: 0 bytes in 0 blocks.
==7480==      possibly lost: 68 bytes in 1 blocks.
==7480==    still reachable: 0 bytes in 0 blocks.
==7480==         suppressed: 0 bytes in 0 blocks.
==7480== Reachable blocks (those to which a pointer was found) are not shown.
==7480== To see them, rerun with: --show-reachable=yes