AKRESULT __cdecl AK::SoundEngine::UnloadBank	(	const char *	in_pszString,
		const void *	in_pInMemoryBankPtr,
		AkMemPoolId *	out_pMemPoolId = `NULL`
	)

Unload a bank synchronously.
Refer to General Information for a discussion on using strings and IDs.

Returns:: AK_Success if successful, AK_Fail otherwise. AK_Success is returned when the bank was not loaded.

Remarks:

If you provided a pool memory ID when loading this bank, it is returned as well. Otherwise, the function returns AK_DEFAULT_POOL_ID.
The sound engine internally calls GetIDFromString(in_pszString) to retrieve the bank ID, then it calls the synchronous version of UnloadBank() by ID. Therefore, in_pszString should be the real name of the SoundBank (with or without the "bnk" extension - it is trimmed internally), not the name of the file (if you changed it), nor the full path of the file.
In order to force the memory deallocation of the bank, sounds that use media from this bank will be stopped. This means that streamed sounds or generated sounds will not be stopped.

See also:

Parameters:

	in_pszString	Name of the bank to unload
	in_pInMemoryBankPtr	Memory pointer from where the bank was initially loaded from. (REQUIRED to determine which bank associated toa memory pointer must be unloaded). Pass NULL only if NULL was passed when loading the bank.
	out_pMemPoolId	Returned memory pool ID used with LoadBank() (can pass NULL)

Wwise SDK 2015.1.9