Modern Fs MemoryMappedFile Open

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MemoryMappedFile.Open

Maps a file into memory, read-only unless writable is true; an empty file fails.

Syntax

MemoryMappedFile.Open( p [, writable ] )

Notes

• FsResultBool

Examples

#import "std/fs"
using fs

dim td as FsResultUStr = CreateTempDir( "fbdoc" )
dim as ustring dir_ = td.Value( )
dim as ustring p = PathJoin( dir_, "f.txt" )
WriteAllText( p, "hello" )

dim mm as MemoryMappedFile

'' Read-only by default; pass TRUE for a writable mapping
print mm.Open( p ).IsOk( )   '' true
print mm.IsOpen( )           '' true
print mm.Size( )             '' 5

mm.Close( )

'' AN EMPTY FILE CANNOT BE MAPPED -- there is no region to map, and both
'' platforms refuse it
dim as ustring empty_ = PathJoin( dir_, "empty.txt" )
WriteAllText( empty_, "" )
print mm.Open( empty_ ).IsOk( )           '' false

RemoveDirAll( dir_ )

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Library: Filesystem Library
Category: Filesystem
Documented under: Locking, Mapping And Watching