Inside Macintosh: Sound
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You can use the SysBeep procedure to play the system alert sound, the SndPlay function to play the sound stored in any 'snd ' resource, and the SndStartFilePlay function to play a sound file.
You can use the SysBeep procedure to play the system alert sound.
PROCEDURE SysBeep (duration: Integer);
The SysBeep procedure causes the Sound Manager to play the system alert sound at its current volume. If necessary, the Sound Manager loads into memory the sound resource containing the system alert sound and links it to a sound channel. The user selects a system alert sound in the Alert Sounds subpanel of the Sound control panel.
The volume of the sound produced depends on the current setting of the system alert sound volume, which the user can adjust in the Alert Sounds subpanel of the Sound control panel. The system alert sound volume can also be read and set by calling the GetSysBeepVolume and SetSysBeepVolume routines. If the volume is set to 0 (silent) and the system alert sound is enabled, calling SysBeep causes the menu bar to blink once.
You can use the SndPlay function to play a sound resource that your application has loaded into memory.
FUNCTION SndPlay (chan: SndChannelPtr; sndHdl: Handle;
async: Boolean): OSErr;
The SndPlay function attempts to play the sound located at sndHdl , which is expected to have the structure of a format 1 'snd ' resource. If the resource has not yet been loaded, the SndPlay function fails and returns the resProblem result code. The handle you pass in the sndHdl parameter must be locked for as long as the sound is playing asynchronously.
The chan parameter is a pointer to a sound channel. If chan is not NIL , it is used as a valid channel. If chan is NIL , an internally allocated sound channel is used. Commands and data contained in the sound handle are then sent to the channel. Note that you can pass SndPlay a handle to some data created by calling the Sound Input Manager's SndRecord function as well as a handle to an actual 'snd ' resource that you have loaded into memory.
Because the SndPlay function moves memory, you should not call it at interrupt time.
For an example of how to play a sound resource using the SndPlay function, see "Playing a Sound Resource" . For more information on the SndPlay function, see the chapter "Sound Manager" in this book.
You can call the SndStartFilePlay function to initiate a play from disk.
FUNCTION SndStartFilePlay (chan: SndChannelPtr; fRefNum: Integer;
resNum: Integer; bufferSize: LongInt;
theBuffer: Ptr;
theSelection: AudioSelectionPtr;
theCompletion: ProcPtr;
async: Boolean): OSErr;
The SndStartFilePlay function begins a continuous play from disk on a sound channel. The chan parameter is a pointer to the sound channel. If chan is not NIL , it is used as a valid channel. If chan is NIL , an internally allocated sound channel is used for play from disk. This internally allocated sound channel is not passed back to you. Because SndPauseFilePlay and SndStopFilePlay (described in the chapter "Sound Manager") require a sound-channel pointer, you must allocate your own channel if you wish to use those routines.
The sounds you wish to play can be stored either in a file or in an 'snd ' resource. If you are playing a file, then fRefNum should be the file reference number of the file to be played and the parameter resNum should be set to 0. If you are playing an 'snd ' resource, then fRefNum should be set to 0 and resNum should be the resource ID number (not the file reference number) of the resource to play.
Because the SndStartFilePlay function moves memory, you should not call it at interrupt time.
The trap macro and routine selector for the SndStartFilePlay function are
For an example of how to play a sound file using the SndStartFilePlay function, see "Playing a Sound File" . For information on completion routines, see the chapter "Sound Manager" in this book.
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