MATLAB Programming

Accessing Files with Memory-Mapping
The following command constructs a memmapfile object for the entire file
records.dat, and sets the Format property for that object to uint64. Any
read or write operations made via the memory map will read and write the
file contents as a sequence of unsigned 64-bit integers:
m = memmapfile('records.dat', 'Format', 'uint64')
Filename: 'd:\matlab\mfiles\records.dat'
Writable: false
Offset: 0
Format: 'uint64'
Repeat: Inf
Data: 5000x1 uint64 array
You can change the value of the Format property at any time after the
memmapfile object is constructed. Use the object.property syntax shown
here in assigning the new value:
m.Format = 'int32';
Further read and write operations to the region mapped by m will now treat
the data in the file as a sequence of signed 32-bit integers.
Property names, like Format, arenotcasesensitive.
Formatting the Mapped Data to an Array. You can also specify an
array shape to be applied to the data read or written to the mapped file,
andafieldnametobeusedinreferencing this array. Use a cell array to
hold these values either when calling the memmapfile constructor or when
modifying m.Format after the object has been constructed. The cell array
containsthreeelements:thedatatypetobeappliedtothemappedregion,
the dimensions of the array shape that is applied to the region, and a field
name to use in referencing the data:
objname = memmapfile(filename, ...
'Format', {datatype, dimensions, varname})
The command below constructs a memmapfile object for a region of
records.dat such that the contents of the region are handled by MATLAB as
a 4-by-10-by-18 array of unsigned 32-bit integers, and can be referenced in the
structure of the returned object using the field name x:
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