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Inside Macintosh: Files /

Chapter 1 - Introduction to File Management / File Management Reference

File Access Routines / Manipulating the End-of-File

SetEOF

You can use the SetEOF function to set the logical end-of-file of an open file.

FUNCTION SetEOF (refNum: Integer; logEOF: LongInt): OSErr;

refNum

The file reference number of an open file.

logEOF

The logical end-of-file.

DESCRIPTION

The SetEOF function sets the logical end-of-file of the specified file. If you attempt to set the logical end-of-file beyond the physical end-of-file, the physical end-of-file is set 1 byte beyond the end of the next free allocation block; if there isn't enough space on the volume, no change is made, and SetEOF returns dskFulErr as its function result.

If you set the logEOF parameter to 0, all space occupied by the file on the volume is released. The file still exists, but it contains 0 bytes. Setting a file fork's end-of-file to 0 is therefore not the same as deleting the file (which removes both file forks at once).

RESULT CODES

noErr	0	No error
dskFulErr	-34	Disk full
ioErr	-36	I/O error
fnOpnErr	-38	File not open
wPrErr	-44	Hardware volume lock
fLckdErr	-45	File is locked
vLckdErr	-46	Software volume lock
rfNumErr	-51	Bad reference number
wrPermErr	-61	Read/write permission doesn't allow writing

SEE ALSO

For a description of the logical and physical end-of-file, see the section "File Access Characteristics" on page 1-8.