This function installs an I/O procedure in the MMIO I/O procedure table, removes a procedure from the table, or finds a procedure when given its FOURCC identifier.

#define INCL_MMIOOS2
#include <os2.h>

FOURCC       fccIOProc;  /*  Four-character code. */
PMMIOPROC    pIOProc;    /*  IOProc address. */
ULONG        ulFlags;    /*  Flags. */
PMMIOPROC    rc;         /*  Address of the IOProc. */

rc = mmioInstallIOProc(fccIOProc, pIOProc,
       ulFlags);