mmioInstallIOProc function

The mmioInstallIOProc function installs or removes a custom I/O procedure. This function also locates an installed I/O procedure, using its corresponding four-character code.

Syntax

LPMMIOPROC mmioInstallIOProc(
   FOURCC     fccIOProc,
   LPMMIOPROC pIOProc,
   DWORD      dwFlags
);

Parameters

• fccIOProc
  Four-character code identifying the I/O procedure to install, remove, or locate. All characters in this code should be uppercase.

• pIOProc
  Pointer to the I/O procedure to install. To remove or locate an I/O procedure, set this parameter to NULL. For more information about the I/O procedure, see MMIOProc.

• dwFlags
  Flag indicating whether the I/O procedure is being installed, removed, or located. The following values are defined.

  Value	Meaning
  MMIO_FINDPROC	Searches for the specified I/O procedure.
  MMIO_GLOBALPROC	This flag is a modifier to the MMIO_INSTALLPROC flag and indicates the I/O procedure should be installed for global use. This flag is ignored if MMIO_FINDPROC or MMIO_REMOVEPROC is specified.
  MMIO_INSTALLPROC	Installs the specified I/O procedure.
  MMIO_REMOVEPROC	Removes the specified I/O procedure.

   

Return value

Returns the address of the I/O procedure installed, removed, or located. Returns NULL if there is an error.

Requirements