Question

can someone confirm whether this is indeed a bug? ( If so I will go off and file it with Apple ).

attempting to fetch kAudioSessionProperty_AudioRoute is returning error code kAudioSessionUnsupportedPropertyError on any version of the simulator prior to 4.3 ( which is the latest version at time of writing ).

this one is dead easy to reproduce.

Start a new project ( I am using Xcode 4.0.2 Build 4A2002a, that is the standard build ), window-based project “AudioSessionBug”

include AudioToolbox framework

replace the application delegate’s .m file with the following:

//
//  AudioSessionBugAppDelegate.m
//  AudioSessionBug
//
//  Created by Pi on 02/07/2011.
//  Copyright 2011 Pi. All rights reserved.
//

#import "AudioSessionBugAppDelegate.h"

#import <AudioToolbox/AudioToolbox.h>

#define SET_PROPERTY( prop, type, val ) \
{ \
OSStatus ret = AudioSessionSetProperty( prop, sizeof( type ), &(type){ val } ); \
if ( ret != kAudioSessionNoError ) \
{ \
NSLog( @"AudioSessionSETProperty failed for: %s!", #prop ); \
return; \
} \
}

enum  {
    kNo = 0,
    kYes = 1
};

// - - - 

@interface AudioSessionBugAppDelegate ( )

- (void) setupSession;

@end

// - - - 

@implementation AudioSessionBugAppDelegate


@synthesize window=_window;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
    // Override point for customization after application launch.
    [self.window makeKeyAndVisible];


    [self setupSession];


    return YES;
}

- (void) setupSession
{
    OSStatus result = AudioSessionInitialize( NULL, NULL, NULL, NULL );
    assert( result == kAudioSessionNoError );

    SET_PROPERTY( kAudioSessionProperty_AudioCategory,  UInt32,   kAudioSessionCategory_PlayAndRecord );

    // make sure headphones are plugged in!
    {
        // http://stackoverflow.com/questions/2753562/what-kind-of-routes-could-i-get-back-from-kaudiosessionproperty-audioroute-proper
        CFStringRef state = nil;        
        UInt32 propertySize = sizeof(CFStringRef);
        OSStatus status = AudioSessionGetProperty( kAudioSessionProperty_AudioRoute, &propertySize, &state );

        if ( status == kAudioSessionUnsupportedPropertyError )
        {
            NSLog( @" WTF? GETTING kAudioSessionProperty_AudioRoute GIVES kAudioSessionUnsupportedPropertyError ?!?!? " );
        }

        NSLog( @" OK - done! " );

        exit( 1 );
    }
}

- (void)dealloc
{
    [_window release];
    [super dealloc];
}

@end

check that it works.

now change deployment target to anything prior to 4.3. say 4.2.

run it again on iPad simulator 4.3 — OK
run it again on iPad simulator 4.2 — FAIL

Answer 1

I just received the following confirmation from Apple:

This was a bug that was fixed in 4.3 and we currently have no plans to fix bugs in earlier builds of the simulator.