afQuery
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afQuery queries the capabilities of the Audio File Library.
SYNOPSIS
#include <audiofile.h>
AUpvlist afQuery (int querytype, int arg1, int arg2, int arg3, int arg4);
long afQueryLong (int querytype, int arg1, int arg2, int arg3, int arg4);
double afQueryDouble (int querytype, int arg1, int arg2, int arg3, int arg4);
void *afQueryPointer (int querytype, int arg1, int arg2, int arg3, int arg4);
PARAMETERS
querytype can be one of the following:
AF_QUERYTYPE_FILEFMT
AF_QUERYTYPE_INST
AF_QUERYTYPE_INSTPARAM
AF_QUERYTYPE_COMPRESSION
AF_QUERYTYPE_COMPRESSIONPARAM
AF_QUERYTYPE_MISC
AF_QUERYTYPE_MARK
AF_QUERYTYPE_LOOP
For AF_QUERYTYPE_FILEFMT, the following selectors are valid values for arg1:
AF_QUERY_LABEL - Request a short label string for the format (e.g., "aiff").
AF_QUERY_NAME - Request a short name for the format (e.g., "MS RIFF WAVE").
AF_QUERY_DESC - Request a descriptive name for the format (e.g., "Audio
Interchange File Format").
AF_QUERY_IMPLEMENTED - Request a boolean value indicating whether the
format is implemented for reading and writing in the Audio File Library.
AF_QUERY_ID_COUNT - Request the total number of formats implemented.
AF_QUERY_IDS - Request an integer array of the id token values of all
implemented file formats.
AF_QUERY_COMPRESSION_TYPES - Used with the selector AF_QUERY_VALUE_COUNT
in arg2, this will return a long integer containing the number of
compression schemes available for use within the format specified in arg3.
Used with selector AF_QUERY_VALUES, it returns a pointer to an integer
array containing the compression id values of the compression schemes
supported by the format specified in arg3.
AF_QUERY_SAMPLE_FORMATS - Used with the selector AF_QUERY_DEFAULT in arg2,
this will return the default sample format for the file format specified in
arg3.
AF_QUERY_SAMPLE_SIZES - Used with selector AF_QUERY_DEFAULT in arg2, this
will return the default sample width for the file format specified in arg3.
ERRORS
afQuery can produce the following errors:
* AF_BAD_QUERYTYPE - The query type is unsupported.
* AF_BAD_QUERY - The arguments to the query are bad.