OpenAL detects only a subset of those conditions that could be considered
errors. This is because in many cases error checking would adversely impact
the performance of an error-free program. The state variable alErrors is
used to obtain error information. When an error is detected by AL, a flag is
set and the error code is recorded. Further errors, if they occur, do not
affect this recorded code. When alErrors is read, the error is returned and
the flag is cleared, so that a further error will again record its code. If
reading alErrors returns  then there has been no detectable error
since the last time alErrors (or since the AL was initialized).
When an error flag is set, results of AL operations are undefined only if
ALOutOfMemory has occurred. In other cases, the command generating the
error is ignored so that it has no effect on AL state or output buffer
contents. If the error generating command returns a value, it returns zero.
If the generating command modifies values through a pointer argument, no
change is made to these values. These error semantics apply only to AL
errors, not to system errors such as memory access errors.