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Important: The information in this document is obsolete and should not be used for new development.

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Inside Macintosh: Files /
Chapter 2 - File Manager / File Manager Reference
High-Level File Access Routines / Allocating File Blocks


Allocate

You can use the Allocate function to allocate additional blocks to an open file.

FUNCTION Allocate (refNum: Integer; VAR count: LongInt): OSErr;
refNum
The file reference number of an open file.
count
On input, the number of additional bytes to allocate to the file; on output, the number of bytes actually allocated, rounded up to the nearest multiple of the allocation block size.
DESCRIPTION
The Allocate function adds the specified number of bytes to the specified file and sets the physical end-of-file to 1 byte beyond the last block allocated. If there isn't enough empty space on the volume to satisfy the allocation request, Allocate allocates the rest of the space on the volume and returns dskFulErr as its function result.

The Allocate function always attempts to allocate contiguous blocks. If the total number of requested bytes is unavailable, Allocate allocates whatever space, contiguous or not, is available. To force the allocation of the entire requested space as a contiguous piece, call AllocContig instead.

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

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© Apple Computer, Inc.
2 JUL 1996