ALqueryparams(3dm)                                          ALqueryparams(3dm)



NAME
     ALqueryparams - (obsolete) get descriptor/description pairs for audio
     device state variables

SYNOPSIS
     #include <dmedia/audio.h>

     long ALqueryparams(long device, long *PVbuffer, long bufferlength)

PARAMETER
     device         expects a device.  Currently, there is only one device,
                    AL_DEFAULT_DEVICE.

     PVbuffer       expects an array of longs into which ALqueryparams(3dm)
                    can write descriptor/description pairs for each state
                    variable associated with device.  The even (0,2,4, ...)
                    entries receive the descriptors. The odd entries (1,3,5,
                    ...) receive the descriptions.  These descriptions take on
                    one of four values:

                    +/-ALRANGEVALUE if this device state variable can assume
                    a range of values, and the range has some meaning, i.e.
                    larger values mean more of whatever this parameter
                    controls.  A value of -ALRANGEVALUE indicates that the
                    parameter is read-only.

                    +/-ALENUMVALUE  if this device state variable assumes
                    values from an enumerated type.  They still have a limited
                    range, but there is no inherent relationship between them.
                    A value of -ALENUMVALUE indicates that the parameter is
                    read-only.

     bufferlength   expects the length of the buffer, in longs, pointed to by
                    PVbuffer.

DESCRIPTION
     ALqueryparams is obsolete and is provided for backward compatibility. The
     preferred method is to use alQueryValues(3dm) with the AL_PARAMS
     parameter to list the supported parameters, followed by
     alGetParamInfo(3dm) to get information about each supported parameter.

     ALqueryparams(3dm) lets you get a list of descriptors for all the state
     variables associated with the specified device.

     ALqueryparams(3dm) also tells you whether the value of a state variable
     must be one of a set of enumerated types or any number within a specific
     range.  In both cases the values are numbers within the range returned by
     ALgetminmax(3dm) and have the default value returned by
     ALgetdefault(3dm).






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ALqueryparams(3dm)                                          ALqueryparams(3dm)



     Typical device parameters are expected to be things like volume and
     sample rate. You can find a list of parameters and their descriptions in
     ALgetparams(3dm).

     ALqueryparams(3dm) returns the length of the buffer (number of longs)
     that is required to hold all pairs of descriptors/descriptions. If
     PVbuffer is smaller than this value, you have not acquired a complete
     list of descriptor/description pairs and should increase your PVbuffer
     and try again.

     To simply determine the size of the buffer needed to hold the parameters
     and descriptions, call ALqueryparams(3dm) with bufferlength set to zero.

     ALqueryparams(3dm) can fail for the following reasons:

     ALBADDEVICE             device is not valid.

     ALBADPVBUFFER           PVbuffer is null valued.

     ALBADBUFFERLENGTHODD   bufferlength is odd.

     ALBADBUFFERLENGTHNEG   bufferlength is negative.

     ALBADDEVICEACCESS      audio hardware is inaccessible.

EXAMPLE
               #include <dmedia/audio.h>
               #include <malloc.h>
               ...
               /* Get a buffer containing all the device parameters. */
               long *buf,buflen;
               buflen=ALqueryparams(AL_DEFAULT_DEVICE,0,0);
               buf=(long *)malloc(buflen*sizeof(long));
               (void)ALqueryparams(AL_DEFAULT_DEVICE,buf,buflen);


DIAGNOSTICS
     Upon successful completion ALqueryparams(3dm) returns the size of the
     buffer, in longs, needed to hold all the descriptor/description pairs for
     device. Otherwise, ALqueryparams(3dm) returns -1 and sets an error number
     which can be retrieved with oserror(3C).

SEE ALSO
     ALgetparams(3dm), ALsetparams(3dm), ALgetminmax(3dm), ALgetname(3dm),
     ALgetdefault(3dm), ALsetdevice(3dm), oserror(3C)










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