The acmFormatChoose function creates an ACM-defined dialog box that enables the user to select a waveform-audio format.

MMRESULT acmFormatChoose(



Pointer to an ACMFORMATCHOOSE structure that contains information used to initialize the dialog box. When this function returns, this structure contains information about the user's format selection.

The pwfx member of this structure must contain a valid pointer to a memory location that will contain the returned format header structure. Moreover, the cbwfx member must be filled in with the size, in bytes, of this memory buffer.

Return Values

Returns MMSYSERR_NOERROR if successful or an error otherwise. Possible return values include the following.

Value Description
ACMERR_CANCELED The user chose the Cancel button or the Close command on the System menu to close the dialog box.
ACMERR_NOTPOSSIBLE The buffer identified by the pwfx member of the ACMFORMATCHOOSE structure is too small to contain the selected format.
MMSYSERR_INVALFLAG At least one flag is invalid.
MMSYSERR_INVALHANDLE The specified handle is invalid.
MMSYSERR_INVALPARAM At least one parameter is invalid.
MMSYSERR_NODRIVER A suitable driver is not available to provide valid format selections.


  Windows NT/2000/XP: Included in Windows NT 3.1 and later.
  Windows 95/98/Me: Included in Windows 95 and later.
  Header: Declared in Msacm.h.
  Library: Use Msacm32.lib.
  Unicode: Implemented as Unicode and ANSI versions on Windows NT/2000/XP.

See Also

Audio Compression Manager, Audio Compression Functions, ACMFORMATCHOOSE