## MMPM/2 Device Driver Reference

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### AUDIO_BUFFER (43h) - Returns

The amount of data is expressed as the number of bytes currently in the queues. Notice that the amount of queue data that this IOCtl returns is accurate only at the point in time this value is determined. The amount of queued data can be different at any other point in time.

If the size of the buffer contents can be represented as an amount of time, that amount of time is returned in the fields ulReadBufTime and ulWriteBufTime. If not, the values returned are -1. To help determine the optimal size of the Read and Write kernel buffer queues, the maximum number of bytes that these queues have ever contained is returned in ulReadBufMax and ulWriteBufMax.

Refer to the OS/2 Control Program Guide and Reference for more information on the return code for DosDevIOCtl.