I figured it out. I'm an idiot. There was an error in the macro I had wrapping the call & reporting the error, which called the AudioSessionInitialize twice. That doesn't quite explain the error code I saw, but it sure isn't worth wondering about.
UPDATE: Actually this is pretty slapstick so I'm going to explain.
The offending macro was originally:
#define CHECK(S) { OSStatus err = (S); if (S) printf("Error %x at \"%s\"\n", err, #S);}
so bug #1 is the if (S)
which should be if if (err)
. Hence I'm repeating every call to the audio system, which explains various other weird things, so I'm very happy I tried to figure out what had seemed like a harmless anomaly. In this case the second call complained that the audio session was already initialized.
But why the weird error code? I wanted to see the 4CC's so I changed the macro to this, carrying the error along:
#define CHECK(S) { OSStatus err[2] = {S,0}; if (S) printf("Error %x '%4s' at \"%s\"\n", err, &err, #S); }
(The second OSStatus of 0 terminates the string defined by the 4CC first OSStatus, so I can print it with format %s
.) But I forgot to change err
to err[0]
, so it was indeed printing the address of the err
array. This I'm pretty sure is correct now:
#define CHECK(S) { OSStatus err[2] = {S,0}; if (*err) printf("Error %x '%4s' at \"%s\"\n", *err, err, #S); }