ACMDRVOPENDESC (Compact 2013)

3/26/2014

This structure is used by the ACM for passing information to an ACM driver after the ACM sends the driver an ACM_Open function.

Syntax

typedef struct { 
  DWORD cbStruct; 
  FOURCC fccType; 
  FOURCC fccComp; 
  DWORD dwVersion; 
  DWORD dwFlags; 
  DWORD dwError; 
  LPCSTR pszSectionName; 
  LPCSTR pszAliasName; 
  DWORD dnDevNode;
} ACMDRVOPENDESC;

Members

• cbStruct
  Value that specifies the size, in bytes, of the structure.

• fccType
  Value that contains a four-character code identifying the driver type. The driver must compare this value with ACMDRIVERDETAILS_FCCTYPE_AUDIOCODEC, which is declared in the Msacm.h header file, to equal the string "audc". If the member contents do not match this string, the driver must fail the open request by specifying an ACM_IOControl return value of 0.

• fccComp
  Not used. Defined to contain a four-character code identifying the driver sub-type.

• dwVersion
  Value that specifies the ACM's version number. The version number format is 0xAABBCCCC, where AA is the major version number, BB is the minor version number, and CCCC is the build number. This value is also returned by the ACM's acmGetVersion function.

• dwFlags
  No flags currently are defined. This member is identical to the fdwOpen argument passed to the acmDriverOpen function.

• dwError
  Value that specifies an error code. Drivers are restricted to specifying an ACM_IOControl return value of 0 for all errors. To provide better error reporting, ACM drivers can specify an error code in this member if they also set the ACM_IOControl function's return value to 0. The error code can be one of the MMSYSERR error codes declared in the Mmsystem.h header file or one of the ACMERR error codes declared in the Msacm.h header file.

• pszSectionName
  Pointer to the registry key under which the driver's alias is stored.

• pszAliasName
  Pointer to the driver's alias.

• dnDevNode
  Value that specifies a device node identifier.

Remarks

When the ACM calls an ACM driver's ACM_IOControl entry point and specifies a DRV_OPEN message, it includes an ACMDRVOPENDESC structure as the lParam2 member of ACM_IOControl. The ACM sends a DRV_OPEN message when an application calls the acmDriverOpen function.

Requirements

See Also

Reference

ACM Driver Structures
ACM_Open (ACM Driver)
ACM_IOControl
ACM Driver Messages