# SDL: audio: Fix some logic errors in the new device hashtable code.

**URL:** <https://discourse.libsdl.org/t/sdl-audio-fix-some-logic-errors-in-the-new-device-hashtable-code/46613>\
**Category:** SDL Commits\
**Created:** [October 15, 2023, 3:12am UTC](https://discourse.libsdl.org/t/sdl-audio-fix-some-logic-errors-in-the-new-device-hashtable-code/46613 "2023-10-15T03:12:02Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![SDLPushPostBot](https://discourse.libsdl.org/user_avatar/discourse.libsdl.org/sdlpushpostbot/32/4370_2.png) [@SDLPushPostBot](https://discourse.libsdl.org/u/SDLPushPostBot)\
**Post date:** [October 15, 2023, 3:12am UTC](https://discourse.libsdl.org/t/sdl-audio-fix-some-logic-errors-in-the-new-device-hashtable-code/46613/1 "2023-10-15T03:12:02Z")

</div>

> <https://github.com/libsdl-org/SDL/commit/b22ffb979725fe3b502e5e8eddbe71955c5adf74>
>
> Fixes #8395.

```diff
From b22ffb979725fe3b502e5e8eddbe71955c5adf74 Mon Sep 17 00:00:00 2001
From: "Ryan C. Gordon" <[EMAIL REDACTED]>
Date: Sat, 14 Oct 2023 23:10:50 -0400
Subject: [PATCH] audio: Fix some logic errors in the new device hashtable
 code.

Fixes #8395.
---
 src/audio/SDL_audio.c | 34 ++++++++++++++++++++++------------
 1 file changed, 22 insertions(+), 12 deletions(-)

diff --git a/src/audio/SDL_audio.c b/src/audio/SDL_audio.c
index a14bef9cc2e9..3321050d1d94 100644
--- a/src/audio/SDL_audio.c
+++ b/src/audio/SDL_audio.c
@@ -256,9 +256,12 @@ static SDL_AudioDeviceID AssignAudioDeviceInstanceId(SDL_bool iscapture, SDL_boo
 // this assumes you hold the _physical_ device lock for this logical device! This will not unlock the lock or close the physical device!
 static void DestroyLogicalAudioDevice(SDL_LogicalAudioDevice *logdev)
 {
- SDL_LockRWLockForWriting(current_audio.device_hash_lock);
- SDL_RemoveFromHashTable(current_audio.device_hash, (const void *) (uintptr_t) logdev->instance_id);
- SDL_UnlockRWLock(current_audio.device_hash_lock);
+ // Remove ourselves from the device_hash hashtable.
+ if (current_audio.device_hash) { // will be NULL while shutting down.
+ SDL_LockRWLockForWriting(current_audio.device_hash_lock);
+ SDL_RemoveFromHashTable(current_audio.device_hash, (const void *) (uintptr_t) logdev->instance_id);
+ SDL_UnlockRWLock(current_audio.device_hash_lock);
+ }
 
     // remove ourselves from the physical device's list of logical devices.
     if (logdev->next) {
@@ -773,9 +776,14 @@ void SDL_QuitAudio(void)
     const void *value;
     void *iter = NULL;
     while (SDL_IterateHashTable(device_hash, &key, &value, &iter)) {
- SDL_AudioDevice *device = (SDL_AudioDevice *) value;
- SDL_AtomicSet(&device->shutdown, 1);
- DestroyPhysicalAudioDevice(device);
+ // bit #1 of devid is set for physical devices and unset for logical.
+ const SDL_AudioDeviceID devid = (SDL_AudioDeviceID) (uintptr_t) key;
+ const SDL_bool isphysical = (devid & (1<<1)) ? SDL_TRUE : SDL_FALSE;
+ if (isphysical) {
+ SDL_AudioDevice *device = (SDL_AudioDevice *) value;
+ SDL_AtomicSet(&device->shutdown, 1);
+ DestroyPhysicalAudioDevice(device);
+ }
     }
 
     // Free the driver data
@@ -1513,12 +1521,14 @@ SDL_AudioDeviceID SDL_OpenAudioDevice(SDL_AudioDeviceID devid, const SDL_AudioSp
         }
         SDL_UnlockMutex(device->lock);
 
- SDL_LockRWLockForWriting(current_audio.device_hash_lock);
- const SDL_bool inserted = SDL_InsertIntoHashTable(current_audio.device_hash, (const void *) (uintptr_t) retval, logdev);
- SDL_UnlockRWLock(current_audio.device_hash_lock);
- if (!inserted) {
- SDL_CloseAudioDevice(retval);
- retval = 0;
+ if (retval) {
+ SDL_LockRWLockForWriting(current_audio.device_hash_lock);
+ const SDL_bool inserted = SDL_InsertIntoHashTable(current_audio.device_hash, (const void *) (uintptr_t) retval, logdev);
+ SDL_UnlockRWLock(current_audio.device_hash_lock);
+ if (!inserted) {
+ SDL_CloseAudioDevice(retval);
+ retval = 0;
+ }
         }
     }
 

```