Microsoft Windows CE 3.0  

ACMDRVSTREAMINSTANCE

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This structure describes an instance of a conversion stream.

typedef struct {
DWORD
cbStruct
;
LPWAVEFORMATEX
pwfxSrc
;
LPWAVEFORMATEX
pwfxDst
;
LPWAVEFILTER
pwfltr
;
DWORD
dwCallback
;
DWORD
dwInstance
;
DWORD
fdwOpen
;
DWORD
fdwDriver
;
DWORD
dwDriver
;
HACMSTREAM
has
;
} ACMDRVSTREAMINSTANCE;

Members

cbStruct
Specifies the size, in bytes, of this structure.
pwfxSrc
Pointer to a WAVEFORMATEXstructure that defines the source format for a conversion stream.
pwfxDst
Pointer to a WAVEFORMATEXstructure that defines the destination format for a conversion stream.
pwfltr
Pointer to an optional WAVEFILTERstructure that defines a filter to be used on a conversion stream. This member is NULL if the application has not specified a filter.
dwCallback
Specifies the application-specified dwCallbackparameter of the acmStreamOpenfunction.
dwInstance
Specifies the application-specified dwInstanceparameter of acmStreamOpen.
fdwOpen
Specifies the application-specified dwOpenparameter of acmStreamOpen, which consists of a set of flags.
fdwDriver
Specifies driver-defined stream instance information. Although it is intended for storing flag values, an ACM driver can use this member to store any instance-specific DWORDvalue. Because the same ACMDRVSTREAMINSTANCEstructure is passed with all stream messages associated with a particular stream instance, the stored value can be read or modified each time a stream message is received, and the last saved value is available the next time a stream message is received.
dwDriver
Specifies driver-defined stream instance information. An ACM driver can use this member for storing any instance-specific DWORDvalue, such as a pointer to a local, dynamically allocated structure. Because the same ACMDRVSTREAMINSTANCEstructure is passed with all stream messages associated with a particular stream instance, the stored value can be read or modified each time a stream message is received, and the last saved value is available the next time a stream message is received.
has
Specifies the ACM-defined client handle to the open conversion stream.

Remarks

The ACM allocates this structure each time an application calls acmStreamOpen. This structure is then passed to the driver along with all stream messages associated with a particular stream instance. Information in this structure does not change, so if a driver validates information within this structure when it receives an ACMDM_STREAM_OPEN message, it does not have to validate the information again when it receives subsequent messages for the same stream instance.

Requirements

Runs on Versions Defined in Include Link to
Windows CE OS 1.0 and later Msacmdrv.h    
Note   This API is part of the complete Windows CE OS package as provided by Microsoft. The functionality of a particular platform is determined by the original equipment manufacturer (OEM) and some devices may not support this API.


 Last updated on Tuesday, July 13, 2004

© 2004 Microsoft Corporation. All rights reserved.