how to properly release all memory after use?

* how to properly release all memory after use?
       [not found] <1603821572850699902-webhooks-bot@alsa-project.org>
@ 2020-10-27 17:59 ` GitHub issues - opened
  0 siblings, 0 replies; 2+ messages in thread
From: GitHub issues - opened @ 2020-10-27 17:59 UTC (permalink / raw)
  To: alsa-devel

alsa-project/alsa-lib issue #93 was opened from xatian:

```C++
int main () {
    snd_pcm_t* handle;
    int err;
    err = ::snd_pcm_open (&handle, "default", SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK);
    ::printf ("snd_pcm_open: %d\n", err);
    err = ::snd_pcm_close (handle);
    ::printf ("snd_pcm_close: %d\n", err);
    ::snd_config_update_free_global ();
    return 0;
}
```

```
==51583== Memcheck, a memory error detector
==51583== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==51583== Using Valgrind-3.16.1 and LibVEX; rerun with -h for copyright info
==51583== Command: ./alsa-leak
==51583== 
snd_pcm_open: 0
snd_pcm_close: 0
==51583== 
==51583== HEAP SUMMARY:
==51583==     in use at exit: 64,140 bytes in 140 blocks
==51583==   total heap usage: 2,937 allocs, 2,797 frees, 635,030 bytes allocated
==51583== 
==51583== 4 bytes in 1 blocks are definitely lost in loss record 3 of 71
==51583==    at 0x483AB65: calloc (vg_replace_malloc.c:760)
==51583==    by 0x58E0A3E: pa_xmalloc0 (in /usr/lib/x86_64-linux-gnu/libpulse.so.0.21.1)
==51583==    by 0x58B5F9E: pa_context_new_with_proplist (in /usr/lib/x86_64-linux-gnu/libpulse.so.0.21.1)
==51583==    by 0x4848216: ???
==51583==    by 0x4904ABD: ??? (in /usr/lib/x86_64-linux-gnu/libasound.so.2.0.0)
==51583==    by 0x4904F24: ??? (in /usr/lib/x86_64-linux-gnu/libasound.so.2.0.0)
==51583==    by 0x4905849: snd_config_searcha_hooks (in /usr/lib/x86_64-linux-gnu/libasound.so.2.0.0)
==51583==    by 0x4905940: snd_config_searchva_hooks (in /usr/lib/x86_64-linux-gnu/libasound.so.2.0.0)
==51583==    by 0x4905A42: ??? (in /usr/lib/x86_64-linux-gnu/libasound.so.2.0.0)
==51583==    by 0x49042D8: snd_config_search_definition (in /usr/lib/x86_64-linux-gnu/libasound.so.2.0.0)
==51583==    by 0x4920255: ??? (in /usr/lib/x86_64-linux-gnu/libasound.so.2.0.0)
==51583==    by 0x4923227: snd_pcm_open (in /usr/lib/x86_64-linux-gnu/libasound.so.2.0.0)
==51583== 
==51583== 4 bytes in 1 blocks are definitely lost in loss record 4 of 71
==51583==    at 0x483AB65: calloc (vg_replace_malloc.c:760)
==51583==    by 0x58E0A3E: pa_xmalloc0 (in /usr/lib/x86_64-linux-gnu/libpulse.so.0.21.1)
==51583==    by 0x58B5F9E: pa_context_new_with_proplist (in /usr/lib/x86_64-linux-gnu/libpulse.so.0.21.1)
==51583==    by 0x5892577: ???
==51583==    by 0x5891F42: ???
==51583==    by 0x491FC84: ??? (in /usr/lib/x86_64-linux-gnu/libasound.so.2.0.0)
==51583==    by 0x49202E6: ??? (in /usr/lib/x86_64-linux-gnu/libasound.so.2.0.0)
==51583==    by 0x4923227: snd_pcm_open (in /usr/lib/x86_64-linux-gnu/libasound.so.2.0.0)
==51583==    by 0x404A5B: main (src/main.cpp:15)
==51583== 
==51583== LEAK SUMMARY:
==51583==    definitely lost: 8 bytes in 2 blocks
==51583==    indirectly lost: 0 bytes in 0 blocks
==51583==      possibly lost: 0 bytes in 0 blocks
==51583==    still reachable: 64,132 bytes in 138 blocks
==51583==         suppressed: 0 bytes in 0 blocks
==51583== Reachable blocks (those to which a pointer was found) are not shown.
==51583== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==51583== 
==51583== For lists of detected and suppressed errors, rerun with: -s
==51583== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)
```

Did I do something wrong?
What makes matters worse is that if I duplicate the code more leaks get reported so this is not just some global state that gets left behind. And what about the 64kB still reachable?
I am using libasound2 1.2.3.2-1 amd64

Thank you!

Issue URL     : https://github.com/alsa-project/alsa-lib/issues/93
Repository URL: https://github.com/alsa-project/alsa-lib

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