OS/2 Shareware BBS: 10 Tools/10-Tools.zip/tolkit45.zip/os2tk45/samples/mm/mcispy/mcispy.hlp

OS/2 Help File | 1999-05-12 | 9KB | 173 lines

ΓòÉΓòÉΓòÉ 1. Multimedia MCI Message Spy (MCISPY) ΓòÉΓòÉΓòÉ

The Multimedia MCI Message Spy (MCISPY) is a sample program that can be used to
monitor Media Control Interface (MCI) messages that are exchanged between
various devices in the OS/2 Multimedia subsystem. The application is used to
understand the device interactions to application requests in the MMPM/2
subsystem. In order to begin monitoring messages select Spy On pull down from
the menu bar and choose start spying. Messages will be intercepted only after
this choice is made. A description of how MCISPY traps MCI messages Follows.




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                        Γöé Shared Memory  Γöé
                        Γöé  (Named)       Γöé
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       APIs Exported    Γöé                Γöé                     Γöé              Γöé
                        Γöé                Γöé                     Γöé  True MDM    Γöé
                        Γöé  Stub or       Γöé                     Γöé  renamed     Γöé
       mciSendCommand() Γöé  Proxy         Γöé Forwarder entry     Γöé  to MCI.DLL  Γöé
       ΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöñ  MDM.DLL       Γö£ΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöñ containing   Γöé
       mciSendString()  Γöé                Γöé Forwarder entry     Γöé the API      Γöé
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       mdmDriverNotify()Γöé Device Ids     Γöé Forwarder entry     Γöé              Γöé
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                        Γöé Notify Spy     Γöé                     Γöé              Γöé
                        Γöé Application    Γöé                     Γöé              Γöé
                        ΓööΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÿ                     ΓööΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÿ
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                       Γöé Shared Memory   Γöé
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                       Γöé                 Γöé
                       Γöé  MCISPY         Γöé
                       Γöé  Application    Γöé
                       Γöé                 Γöé
                       Γöé                 Γöé
                       Γöé                 Γöé
                       ΓööΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÇΓöÿ

MDM and MCI Message monitoring application interaction.

The above diagram depicts a high level view of how MCI messages are monitored.
MDM is the MCI interface provider. The MCISPY application comprises of an EXE
(MCISPY.EXE) and a corresponding DLL pair. The above diagram depicts the MCISPY
application implementation model. The diagram shows a stub or proxy DLL which
replaces the true MDM.DLL renaming existing MDM to MCI. The proxy MDM exports
the same APIs at the same ordinals as true MDM. The stub or proxy MDM has
forwarder entries into the true MDM (renamed to MCI.DLL) for API workers, ie it
exports the APIs and also imports the same APIs from the true MDM.

MCISPY monitors both the MCI string interface and the MCI command interface.
The display consits of originating Process ID (PID), device Id, MCI message
Flags, User parameter and Data. The above fields are displayed for the MCI
command interface. For the string interface the PID and the string input is
displayed.

The MCISPY application has 5 groups of possible user actions provided for by
the application. The user menu has the following groups of choices. Logfile
enables the user to select a logfile to log the displayed messages. The menubar
pull down choice Enable message Logging item must be selected to turn on
message logging. The Edit group of menu permit editing operations on the
displayed screen contents. Copy,Delete,Discard, and Font operations on the
application screen contents are permitted. The View permits viewing of
installed multimedia devices in the system and also provides a simple MCI Flag
parser. The user enters the Flag value (in hex) and selects a MCI message and
the parser displays what the flag combination is. The Filter pulldown has
various means by which messages can be filtered. The Disable choices (String
Interface,Command Interface, and Driver Notifications) respectively filter
inputs from the above APIs. Filtering by MCI Messages is permitted. If MCI_OPEN
is filtered then the application will not see MCI_OPEN messages at all till it
is turned of. To turn off reinvoke the Filter by Messages choice and select or
deslect the message. Filter by Device types allows a device type filter which
behaves similarly. Filtering by active device Ids is also permitted. There are
provisions to disable frequently occurring timer messages like
MCI_SETPOSITION_ADVISE. MCISPY also displays error return codes as they occur.

To enable logging of messages to a file select enable message logging from the
menu bar under LogFile. Messages will be written to the default log file
"MCISPY.LOG". Select Open to specify a different log file.

The Edit choices are intended for clearing messages on the screen and other
related operations. Copy is supported. Clear All clears all displayed messages.
Select text first before copying. Set font sets the window font.


ΓòÉΓòÉΓòÉ 2. Help for MCISPY Keys ΓòÉΓòÉΓòÉ

The following keys can be used to control the MCISPY App

 Alt+L     Select LogFile from menu bar.

 Alt+E     Select Edit from menu bar.

 Alt+V     Select View from menu bar.

 Alt+F     Select Filter from menu bar.

 Alt+H     Select Help from menu bar.


ΓòÉΓòÉΓòÉ 3. MCISPY Filter MCI Messages ΓòÉΓòÉΓòÉ

You can filter or exclude messages you do not want to see. The list box
contains the list of all Multimedia MCI messages. You can select the message(s)
you want to exclude(not displayed) and select the "OK" pushbutton.

Initially no message filter is in effect and hence all MCI messages are
displayed. The "All" pushbutton selects all items in the listbox. The "None"
pushbutton deselects all items in the listbox. The "Timer on" pushbutton
selects the timer messages like MM_MCIPOSITIONCHANGE. The "Timer Off"
pushbutton deselects the timer messages. the "Actions On" pushbutton selects
the MCI Actions group of messages like MCI_PLAY, MCI_RECORD, MCI_PAUSE,
MCI_RESUME, MCI_SEEK, and MCI_STOP. The 'Actions Off" pushbutton deselects the
actions group. To cancel any existing message filter in effect invoke the
dialog again and exit making a new selection or without selecting anything. All
Internal Filter members for the particular type are reset on entry to the
dialog.


ΓòÉΓòÉΓòÉ 4. MCISPY Device Type Filter ΓòÉΓòÉΓòÉ

You can filter or exclude messages you do not want to see for a particular
device. If the device type filter is in effect for a particular device you will
not see any messages (including String interface) for that device. CAVEAT If
the device was automatically opened by using an element to identify the device
then the filtering may not work. list box contains the list of all Multimedia
device types . You can select the device you want to exclude(not displayed) and
select the "OK" pushbutton. To cancel any existing device type filter invoke
the dialog again and exit without choosing anything.


ΓòÉΓòÉΓòÉ 5. MCISPY Device Id  or Alias Filter ΓòÉΓòÉΓòÉ

You can filter or exclude messages you do not want to see for a particular
device Id or alias. If the device Id filter is in effect for a particular
device Id you will not see any messages for that device id or alias. CAVEAT If
the device was automatically opened by using an element to identify the device
then the filtering may not work. list box contains the list of all Multimedia
device Id(s) and alias(es) currently open . You can select the device Id or
alias you want to exclude(not displayed) and select the "OK" pushbutton. To
cancel any existing device Id or alias filter invoke the dialog again and exit
without choosing anything or something else.


ΓòÉΓòÉΓòÉ 6. MCISPY Display MCI Flag values ΓòÉΓòÉΓòÉ

MCISPY Displays Flag values in hex as seen by the mciSendCommand interface. For
certain predetermined messages you can see the textual representation of the
hex value. For example on MCI_ACQUIRE message a flag value of 102(hex) means
MCI_EXCLUSIVE and MCI_WAIT. Enter the value of the flag in the entry field at
the top (in hex). Select the message for which the flag value was used. Select
Display to display the flag values in the Results list box. Use Clear to clear
the contents of the Results List box. To dismiss dialog select cancel In order
to add additional messages and flag values modify the source code provided.


ΓòÉΓòÉΓòÉ 7. MCISPY View Installed Multimedia Devices ΓòÉΓòÉΓòÉ

This dialog displays all the installed multimedia devices in the system. The
display includes logical device, physical device and product information
associated with each device.


ΓòÉΓòÉΓòÉ 8. MCISPY Open Log File ΓòÉΓòÉΓòÉ

You can open a Log file on any drive or in any directory by using this dialog.
Opening of the Log file merely provides a file name to the application.
Subsequently if logging is enabled all messages will be logged to the file just
opened. The default Log file is MCISPY.LOG in the current directory. Select OK
to dismiss the dialog.