Legacy Document

Inside Macintosh: Interapplication Communication /

Chapter 2 - Edition Manager / Edition Manager Reference

Edition Manager Routines / Reading in Edition Data

ReadEdition

Use the ReadEdition function to read data from an edition. This function reads from the current mark for the specified format.

FUNCTION ReadEdition (whichEdition: EditionRefNum; 
                      whichFormat: FormatType; buffPtr: UNIV Ptr;
                      VAR buffLen: Size): OSErr;

whichEdition

The reference number for the edition.

whichFormat

The format type that you want to read.

buffPtr

A pointer to the buffer into which you want to read the data.

buffLen

The number of bytes that you want to read into the buffer. The ReadEdition function returns the actual number of bytes read in the buffLen parameter.

DESCRIPTION

The ReadEdition function reads data from the edition into the specified buffer. ReadEdition returns in the buffLen parameter the total number of bytes read into the buffer. If the buffLen parameter returns a value smaller than the value you have specified, there is no additional data to read, and the ReadEdition function returns a noErr result code. If you use the ReadEdition function after all data is read in, the ReadEdition function returns an eofErr result code.

You can read data from an edition while a publisher on the same machine is writing data to the same edition. The data that you are reading is the old edition (not the data that the publisher is writing). If the publisher finishes writing data before you are through reading the old edition data, the ReadEdition function returns an abortErr result code. If the ReadEdition function returns an abortErr result code, you should stop trying to read data and use the CloseEdition function with the successful parameter set to FALSE.

Note

The Translation Manager (if it is available) attempts implicit translation under certain circumstances. For instance, it does so when your application attempts to read from an edition a format type that is not in the edition. In this case, the Translation Manager attempts to translate the data into the requested format. For more information, see the chapter "Translation Manager" in Inside Macintosh: More Macintosh Toolbox.

RESULT CODES

noErr	0	No error
abortErr	-27	Publisher has written a new edition
ioErr	-36	I/O error
fnOpnErr	-38	File not open
eofErr	-39	No more data of that format
rfNumErr	-51	Bad edition reference number
noTypeErr	-102	Format not available
editionMgrInitErr	-450	Manager not initialized

SEE ALSO

For an example of the use of ReadEdition, see Listing 2-7 beginning on page 2-42.