Send-message-hook structure.

typedef struct _SMHSTRUCT {
  MPARAM     mp2;    /*  Parameter 2. */
  MPARAM     mp1;    /*  Parameter 1. */
  ULONG      msg;    /*  Message identity. */
  HWND       hwnd;   /*  Window handle. */
  ULONG      model;  /*  Message identity. */
} SMHSTRUCT;

typedef   SMHSTRUCT   * PSMHSTRUCT ;