ACMDRIVERPROC callback function (msacm.h)

Article
02/22/2024

The acmDriverProc function specifies a callback function used with the ACM driver. The acmDriverProc name is a placeholder for an application-defined function name. The actual name must be exported by including it in the module-definition file of the executable or DLL file.

Syntax

ACMDRIVERPROC Acmdriverproc;

LRESULT Acmdriverproc(
  DWORD_PTR unnamedParam1,
  HACMDRIVERID unnamedParam2,
  UINT unnamedParam3,
  LPARAM unnamedParam4,
  LPARAM unnamedParam5
)
{...}

Parameters

unnamedParam1

Identifier of the installable ACM driver.

unnamedParam2

Handle to the installable ACM driver. This parameter is a unique handle the ACM assigns to the driver.

unnamedParam3

ACM driver message.

unnamedParam4

Message parameter.

unnamedParam5

Message parameter.

Return value

Returns zero if successful or an error otherwise.

Remarks

Applications should not call any system-defined functions from inside a callback function, except for PostMessage, timeGetSystemTime, timeGetTime, timeSetEvent, timeKillEvent, midiOutShortMsg, midiOutLongMsg, and OutputDebugStr.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	msacm.h