125 lines
3.9 KiB
Plaintext
125 lines
3.9 KiB
Plaintext
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afQuery(3)
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==========
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NAME
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----
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afQuery, afQueryLong, afQueryDouble, afQueryPointer - query the
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capabilities of the Audio File Library
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SYNOPSIS
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--------
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#include <audiofile.h>
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AUpvlist afQuery (int querytype, int arg1, int arg2, int arg3, int arg4);
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long afQueryLong (int querytype, int arg1, int arg2, int arg3, int arg4);
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double afQueryDouble (int querytype, int arg1, int arg2, int arg3,
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int arg4);
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void *afQueryPointer (int querytype, int arg1, int arg2, int arg3,
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int arg4);
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PARAMETERS
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----------
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'querytype' can be one of the following:
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* `AF_QUERYTYPE_FILEFMT`
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* `AF_QUERYTYPE_INST`
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* `AF_QUERYTYPE_INSTPARAM`
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* `AF_QUERYTYPE_COMPRESSION`
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* `AF_QUERYTYPE_COMPRESSIONPARAM`
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* `AF_QUERYTYPE_MISC`
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* `AF_QUERYTYPE_MARK`
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* `AF_QUERYTYPE_LOOP`
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'arg1', 'arg2', 'arg3', and 'arg4' are integer selectors whose
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meaning depends upon 'querytype'.
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RETURN VALUE
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------------
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Upon success, `afQuery` will return a non-null `AUpvlist` value.
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Upon failure, `afQuery` will return null while `afQueryLong` and
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`afQueryDouble` will return -1 and `afQueryPointer` will return
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null.
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Pointers representing character strings are owned by the Audio File
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Library and must not be freed; all other pointer values must be
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freed by the caller.
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DESCRIPTION
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-----------
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For `AF_QUERYTYPE_FILEFMT`, the following selectors are valid values for 'arg1':
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`AF_QUERY_LABEL`:: Request a short label string for the format (e.g., "aiff").
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`AF_QUERY_NAME`:: Request a short name for the format (e.g., "MS RIFF WAVE").
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`AF_QUERY_DESC`:: Request a descriptive name for the format (e.g., "Audio
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Interchange File Format").
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`AF_QUERY_IMPLEMENTED`:: Request a boolean value indicating whether the
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format is implemented for reading and writing in the Audio File Library.
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`AF_QUERY_ID_COUNT`:: Request the total number of formats implemented.
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`AF_QUERY_IDS`:: Request an integer array of the id token values of all
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implemented file formats.
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`AF_QUERY_COMPRESSION_TYPES`:: Used with the selector AF_QUERY_VALUE_COUNT
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in 'arg2', this will return a long integer containing the number of
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compression schemes available for use within the format specified in 'arg3'.
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Used with selector `AF_QUERY_VALUES`, it returns a pointer to an integer
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array containing the compression id values of the compression schemes
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supported by the format specified in 'arg3'.
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`AF_QUERY_SAMPLE_FORMATS`:: Used with the selector AF_QUERY_DEFAULT in 'arg2',
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this will return the default sample format for the file format specified in
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'arg3'.
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`AF_QUERY_SAMPLE_SIZES`:: Used with selector AF_QUERY_DEFAULT in 'arg2', this
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will return the default sample width for the file format specified in 'arg3'.
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For `AF_QUERYTYPE_INST`, the following selectors are valid for 'arg1':
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`AF_QUERY_SUPPORTED`:: Request a boolean value indicating whether
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the file format in 'arg2' supports instruments.
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`AF_QUERY_MAX_NUMBER`:: Request an integer value indicating the
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maximum number of instruments supported by the file format in 'arg2'.
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For `AF_QUERYTYPE_INSTPARAM`, the following selectors are valid for 'arg1':
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`AF_QUERY_SUPPORTED`:: Request a boolean value indicating whether
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the file format in 'arg2' supports instrument parameters.
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`AF_QUERY_ID_COUNT`:: Request an integer value indicating the number
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of instrument parameters supported by the file format in 'arg2'.
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`AF_QUERY_IDS`:: Request an integer array containing the instrument
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parameter values for the file format in 'arg2'.
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`AF_QUERY_TYPE`:: For the file format in 'arg2', request the type
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of the instrument parameter in 'arg3'.
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`AF_QUERY_NAME`:: For the file format in 'arg2', request the name
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of the instrument parameter in 'arg3'.
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`AF_QUERY_DEFAULT`:: For the file format in 'arg2', request the
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default value of the instrument parameter in 'arg3'.
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ERRORS
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------
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afQuery can produce the following errors:
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`AF_BAD_QUERYTYPE`:: The query type is unsupported.
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`AF_BAD_QUERY`:: The arguments to the query are bad.
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AUTHOR
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------
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Michael Pruett <michael@68k.org>
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