mailslot:A pseudo-file used for one-way interprocess communication.
mapping:A representation of the elements (or points) from a source coordinate space on a target coordinate space.
mapping mode:An algorithm that specifies the size of the units used for any drawing operations associated with a particular device context.
matrix:An n-dimensional array that is used to specify a transformation. Transformations in a two dimensional space require either a two- or three-dimensional array.
Media Control Interface (MCI):High-level control software that provides a device-independent interface to multimedia devices and media files. MCI includes a command-message interface and a command-string interface.
memory DC:See Compatible DC.
menu:A list of items that represent an application's commands. A menu item can be either a string or a bitmap.
menu bar:The topmost menu in a hierarchy of menus. A menu bar typically contains one or more menu items that the user can select to display a pop-up menus.
menu handle:A unique value of the type HMENU used to identify a menu.
menu item:A string or bitmap displayed in a menu. Choosing a menu item either sends a command message or invokes a pop-up menu.
message:A data packet used for communicating information or a request. Messages can be passed between the operating system and an application, different applications, threads within an application, and windows within an application.
message loop:A program loop that retrieves messages from a thread's message queue and dispatches them to the appropriate window procedures.
message mode:Data is written to a named pipe as a stream of messages.
message parameters:A pair of 32-bit values that contain information that a window procedure uses while processing a message.
message queue:A system-defined memory object that holds an ordered list of messages awaiting processing. The system message queue holds mouse and keyboard input waiting to be passed to a thread's message queue. A thread's message queue holds messages waiting to be retrieved by a thread's message loop.
metafile:A metafile is a collection of data structures which store a picture in a device independent format. (There are two metafile formats: the enhanced format and the windows format.)
metafile bits:The binary representation of a metafile; the bits include the header, an optional color palette, an optional text description of the metafile's contents, and the metafile records.
metafile device-context:A device-context that is used for metafile operations.
metafile handle-table:An array of handles which identify pens, brushes, fonts, and other objects that were used to create the picture that is stored in the metafile.
metafile header:A data structure that specifies the size of the picture stored in the metafile, the size of the metafile (in bytes), the number of entries in the metafile's color palette, the number of records in the metafile, a pointer to the metafile description (if one exists), and a pointer to the metafile palette (if one exists).
metafile palette:An array of RGB values which represent the colors used to create the picture that is stored in a metafile.
metafile record:A variable-length data structure. (In most cases, this structure represents a GDI call which was made to create part of the picture which is stored in the metafile.)
MIDI:(Musical Instrument Digital Interface) A standard protocol for communication between musical instruments and computers.
MIDI control-change message:A MIDI message sent to a synthesizer to change different synthesizer control settings. An example of a control-change message is the volume controller message, which changes the volume of a specific MIDI channel.:files have a .MID filename extension. RIFF MIDI files have a .RMI filename extension.
MIDI Mapper:Windows systems software that modifies MIDI output messages and redirects them to a MIDI output device using values stored in a MIDI setup map. The MIDI Mapper can change the destination channel and output device for a message, as well as modify program-change messages, volume values, and key values.
MIDI mapping:The process of translating and redirecting MIDI messages according to data defined in a MIDI map setup.
MIDI program-change message:A MIDI message sent to a synthesizer to change the patch on a specific MIDI channel.
MIDI sequence:Time-stamped MIDI data that can be played by a MIDI sequencer.
MIDI sequencer:A program that creates or plays songs stored as MIDI files. When a sequencer plays MIDI files, it sends MIDI data from the file to a MIDI synthesizer, which produces the sounds. –Windows provides a MIDI sequencer, accessible through MCI, that plays MIDI files.
MIDI setup map:A complete set of data for the MIDI Mapper to use when redirecting MIDI messages. Only one setup map can be in effect at a given time, but the user can have several setup maps available and can choose between them using the MIDI Mapper Control Panel option.:MIDI messages used for synchronizing MIDI sequences with external de-vices. The MCI MIDI sequencer does not support any type of synchronization.
MMA:(MIDI Manufacturers Association) A collective organization composed of MIDI instrument manufacturers and MIDI software companies. The MMA works with the MIDI Standard Committee to maintain the MIDI specification.
module definition file:A text file (.def) that specifies attributes of an executable file or a DLL. A module definition file for a DLL can be used to specify the DLL's name and to list the executable functions that are exported by it. A module definition file for an application can be used to list the DLLs and DLL functions used by the application, to eliminate the need to link the application with an import library.
MS-DOS Date:A date in the format used by MS-DOS. The date is a 16-bit value where bits in the value represent the day, month and year.
MS-DOS Time:A time in the format used by MS-DOS. The time is a 16-bit value where bits in the value represent the hour, minute and second.
MSCDEX:(Microsoft Compact Disc Extensions) A terminate-and-stay-resident (TSR) program that makes CD-ROM drives appear to MS-DOS as network drives. MSCDEX uses hardware-dependent drivers to communicate with a CD-ROM drive.
MSF time format:A time format used by MCI to express time in minutes, seconds, and frames. The number of frames in a second depends on the de-vice type being used. Compact disc audio devices use 75 frames per second. The MSF time format is used primarily by compact disc audio devices.