mmioSendMessage
The mmioSendMessage function sends a message to the I/O procedure associated with a file that was opened with mmioOpen.
Syntax
#define INCL_MMIOOS2 #include <os2.h> LONG mmioSendMessage(HMMIO hmmio, USHORT usMsg, LONG lParam1, LONG lParam2);
Parameters
- usMsg (USHORT) - input
- A message number. See MMIO Messages.
- lParam1 (LONG) - input
- Specifies additional message information. If lParam1 for the particular MMIO message being sent is not a LONG value, cast the value into a LONG data type.
- lParam2 (LONG) - input
- Specifies additional message information. If lParam2 for the particular MMIO message being sent is not a LONG value, cast the value into a LONG data type.
Return Value
- rc (LONG) - returns
- The return code is specific to the message sent. This includes both successful and failed returns. Regarding message-specific return codes, additional information may be contained in the ulErrorRet field of the MMIOINFO structure. This is accessed by calling mmioGetLastError.
- MMIO_ERROR: The message cannot be routed to an IOProc. The handle might be invalid.
- MMIOERR_UNSUPPORTED_MESSAGE: The I/O procedure does not support the message.
Remarks
An application can issue **mmioSendMessage** to send private messages to an installable I/O procedure. This function enables a program to call an I/O procedure directly (unlike system messages, which should be sent by the MMIO Manager).
`MMIOOS2.H` in the `\TOOLKIT\H` subdirectory defines the identifier `MMIOM_USER` so that you can create your own messages. The **mmioSendMessage** function requires that your custom messages be defined between the `MMIOM_USER` and `MMIOM_USER_END` values defined in the header file.
Example Code
The following code illustrates how to send a message to the IOProc to retrieve a handle to a compound file.
HMMIO hmmio1;
USHORT usMsg;
LONG lParam1 = 0L;
LONG lParam2 = 0L;
LONG rc;
...
usMsg = MMIOM_GETCF;
rc = mmioSendMessage(hmmio1, usMsg, lParam1, lParam2);
if (!rc)
{
/* error */
}
else
{
/* rc contains the handle to the compound file */
}
...