Programming

Methods of the memmapfile Class

You can use the following methods on objects constructed from the memmapfile class.

Syntax	Description
disp	Displays properties of the object. The display does not include the object's name.
get(obj)	Returns the values of all properties of the memmapfile object in a structure array.
get(obj, property)	Returns the value of the specified property. property can be a string or cell array of strings, each containing a property name.

Using the disp Method

Use the disp method to display all properties of a memmapfile object. The text displayed includes only the property value, and not the object name or the MATLAB response string, ans =.

Show all properties for object m:

• disp(m)
      Filename: 'd:\matlab\mfiles\records.dat'
      Writable: false
        Offset: 2048
        Format: {'int16' [2 2] 'model'
                 'uint32' [1 1] 'serialno'
                 'single' [1 3] 'expenses'}
        Repeat: Inf
          Data: 753x1 struct array with fields:
              model
           serialno
           expenses
  

Using the get Method

You can use the get method of the memmapfile class to return information on any or all of the object's properties. Specify one or more property names to get the values of specific properties.

This example returns the values of the offset, repeat, and format properties for a memmapfile object. Start by constructing the object:

• m = memmapfile('records.dat', 'offset', 2048, 'format', {  ...
                 'int16'  [2 2] 'model';                     ...
                 'uint32' [1 1] 'serialno';                  ...
                 'single' [1 3] 'expenses'});
  

Use the get method to return the specified property values in a 1-by-3 cell array, m_props:

• m_props = get(m, {'offset', 'repeat', 'format'})
  m_props = 
      [2048]    [Inf]    {3x3 cell}
  
  m_props{3}
  ans = 
      'int16'     [1x2 double]    'model'  
      'uint32'    [1x2 double]    'serialno'
      'single'    [1x2 double]    'expenses'
  

You can also choose to use the objname.property syntax:

• m_props = {m.offset, m.repeat, m.format}
  m_props = 
      [2048]    [Inf]    {3x3 cell}
  

To return the values for all properties with get, pass just the object name:

• get(m)
      Filename: 'd:\matlab\mfiles\records.dat'
      Writable: 0
        Offset: 2048
        Format: {3x3 cell}
        Repeat: Inf
          Data: [753x1 struct]
  

Writing to a Mapped File

Deleting a Memory Map

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