The multimedia input/output (MMIO) file services are an extension of the base OS/2 file services. Designed to be simple, fast, and flexible, the MMIO services-functions, messages, and data structures-enable an application to access and manipulate multimedia data files. These files contain a variety of media elements (images, graphics, digital audio, and video) that are in different file formats; for example, RIFF, AVC, and M-Motion.
MMIO services provide a consistent programming interface so that an application can refer to these files, read and write data to the files, and query the contents of the files, without having to know anything about the specific format of the files. MMIO services strengthen a program's portability, as well as data compatibility, by insulating the application from the underlying file formats.
Note: As a general comment, all fields in MMIO services data structures that are not used in a given function must be initialized to NULL. Flags that are not used, and bits not used within flags, must be set to 0.
The following table describes the MMIO functions.
旼컴컴컴컴컴컴컴컴컴컴컴컴컴컴컫컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� 쿑unction 쿏escription � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioAdvance 쿑ills and empties the contents of an I/O� � 쿫uffer of a file set up for direct I/O � � 쿫uffer access. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioAscend 쿌scends out of a chunk in a RIFF file � � 퀃hat was descended into by mmioDescend � � 쿽r created by mmioCreateChunk. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioCFAddElement 쿌dds an element to the CGRP chunk of an � � 쿽pen RIFF compound file. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioCFAddEntry 쿌dds an entry to the CTOC chunk of an � � 쿽pen RIFF compound file. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioCFChangeEntry 쿎hanges a CTOC entry in an open RIFF � � 쿬ompound file. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioCFClose 쿎loses a RIFF compound file that was � � 쿽pened by mmioCFOpen. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioCFCompact 쿎ompacts the elements of a RIFF compound� � 쿯ile. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioCFCopy 쿎opies the CTOC and CGRP chunks from an � � 쿽pen RIFF compound file to another RIFF � � 쿬ompound file. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioCFDeleteEntry 쿏eletes a CTOC entry in an open RIFF � � 쿬ompound file. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioCFFindEntry 쿑inds a CTOC entry in an open RIFF � � 쿬ompound file. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioCFGetInfo 쿝etrieves the CTOC header of an open � � 쿝IFF compound file. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioCFOpen 쿚pens a RIFF compound file by name. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioCFSetInfo 쿘odifies information that is stored in � � 퀃he CTOC header of an open RIFF compound� � 쿯ile. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioClose 쿎loses a file opened by mmioOpen. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioCreateChunk 쿎reates a chunk in a RIFF file that was � � 쿽pened by mmioOpen. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioDescend 쿏escends into a RIFF file chunk � � 쿫eginning at the current file position, � � 쿽r searches for a specified chunk. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioDetermineSSIOProc 쿏etermines the storage system of the � � 쿺edia data object. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioFindElement 쿐numerates the entries of a compound � � 쿯ile. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioFlush 쿑orces the contents of an I/O buffer to � � 쿫e written to disk. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioFOURCC 쿎onverts four characters to a � � 쿯our-character code (FOURCC). � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioGetFormatName 쿛rovides the descriptive name of the � � 쿯ormat supported by the IOProc. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioGetFormats 쿛rovides a list of all format I/O � � 쿾rocedures available for use. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioGetHeader 쿚btains media-specific information about� � 쿭ata in a file such as the media type, � � 쿺edia structure, and the size of the � � 쿺edia structure. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioGetInfo 쿝etrieves information from the file I/O � � 쿫uffer to a file opened for buffered � � 쿔/O. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioGetLastError 쿝eturns the last error condition stored � � 쿶n ulErrorRet that might contain � � 쿪dditional information for the analysis � � 쿽f the last error routine. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioIdentifyFile 쿏etermines (if possible) the format of a� � 쿯ile by either using the file name or � � 쿿uerying currently installed I/O � � 쿾rocedures to see which IOProc can � � 퀅nderstand and process the specified � � 쿯ile. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioIdentifyStorageSystem 쿔dentifies the storage system that � � 쿬ontains the media data object. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioIniFileCODEC 쿘odifies the initialization file � � �(MMPMMMIO.INI) for MMIO services. It � � 쿪dds, replaces, removes, or finds a � � 쿎ODEC procedure in the MMPMMMIO.INI � � 쿯ile. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioIniFileHandler 쿌dds, replaces, removes, or finds an I/O� � 쿾rocedure in the initialization file � � �(MMPMMMIO.INI). � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioInstallIOProc 쿔nstalls an I/O procedure in the MMIO � � 쿔OProc table, removes an IOProc from the� � 퀃able, or finds a procedure when given � � 쿶ts FOURCC identifier. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioLoadCODECProc 쿗oads the CODEC Proc and returns the � � 쿮ntry point. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioOpen 쿚pens a file and returns an MMIO handle.� 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioQueryCODECName 쿝eturns the CODEC Proc name. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioQueryCODECNameLength 쿝eturns the length of the CODEC Proc � � 쿻ame. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioQueryFormatCount 쿛rovides the number of IOProcs that � � 쿺atch the requested format. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioQueryHeaderLength 쿏etermines the size of the header for a � � 퀂pecified file. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioQueryIOProcModuleHandle 쿛rovides the module handle of an � � 쿔OProc's DLL. This handle must be used � � 퀃o retrieve resources from the DLL. This� � 쿯unction provides the handle of the DLL � � 쿽nly if it was loaded by MMIO from the � � 쿘MPMMMIO.INI file. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioRead 쿝eads a specified number of bytes from a� � 쿯ile opened by mmioOpen. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioRemoveElement 쿝emoves the specified element in a � � 쿬ompound file. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioSeek 쿎hanges the current position for � � 퀁eading, writing, or both, in a file � � 쿽pened by mmioOpen. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioSendMessage 쿞ends a message to the I/O procedure � � 쿪ssociated with a file that was opened � � 퀇ith mmioOpen. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioSet 쿞ets or queries extended file � � 쿶nformation. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioSetBuffer 쿐nables or disables buffered I/O, or � � 쿬hanges the buffer or buffer size, for a� � 쿯ile that was opened using mmioOpen. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioSetHeader 쿞ets media-specific information for data� � 퀃o be written to a file. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioSetInfo 쿎hanges information on a file I/O buffer� � 쿽f a file opened for buffered I/O. � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioStringToFOURCC 쿎onverts a null-terminated string to a � � 쿯our-character code (FOURCC). � 쳐컴컴컴컴컴컴컴컴컴컴컴컴컴컴컵컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴� �mmioWrite 쿥rites to a file that was opened using � � 쿺mioOpen. � 읕컴컴컴컴컴컴컴컴컴컴컴컴컴컴컨컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴컴�