This message requests the IOProc to use the media-specific information when accepting data about, and writing to, the current file or file element. This would include such data as resolution and colors for images, and duration and sample rate for audio. Header translation is expected to be performed when specified.

pmmioinfo (PMMIOINFO)

A pointer to an MMIOINFO data structure.

usMsg (USHORT)

Set to MMIOM_SETHEADER.

lParam1 (LONG)

Pointer to a header buffer that contains the data to be written by the IOProc to the header of the file element. The application is responsible for creating and completing the data structure.

lParam2 (LONG)

Length in bytes of the structure supplied in lParam1.

rc (ULONG)

• Upon successful completion, the number of bytes written is returned.

• For a failure, 0 is returned.

• If the header is invalid, MMIOERR_INVALID_STRUCTURE is set in ulErrorRet.

---

[Back] [Next]