functions (MATLAB Functions)

Return information about function handle

Syntax

```
S = functions(funhandle)
```

Description

S = functions(funhandle) returns, in MATLAB structure S, the function name, type, filename, and other information for the function handle stored in the variable funhandle.

functions does not operate on nonscalar function handles. Passing a nonscalar function handle to functions results in an error.

Caution The functions function is provided for querying and debugging purposes. Because its behavior may change in subsequent releases, you should not rely upon it for programming purposes.

This table lists the standard fields of the return structure.

Field Name
Field Description

function
Function name

type
Function type (e.g., simple, overloaded)

file
The file to be executed when the function handle is evaluated with a nonoverloaded data type

Field Name	Field Description
`function`	Function name
`type`	Function type (e.g., simple, overloaded)
`file`	The file to be executed when the function handle is evaluated with a nonoverloaded data type

Examples

Example 1

To obtain information on a function handle for the poly function, type

f = functions(@poly)
f = 
    function: 'poly'
        type: 'simple'
        file:  '$matlabroot\toolbox\matlab\polyfun\poly.m'

(The term $matlabroot used in this example stands for the file specification of the directory in which MATLAB software is installed for your system. Your output will display this file specification.)

Access individual fields of the returned structure using dot selection notation:

```
f.type
ans = 
   simple
```

Example 2

The function get_handles returns function handles for a subfunction and private function in output arguments s and p respectively:

function [s, p] = get_handles
s = @mysubfun;
p = @myprivatefun;
%
function mysubfun
disp 'Executing subfunction mysubfun'

Call get_handles to obtain the two function handles, and then pass each to the functions function. MATLAB returns information in a structure having the fields function, type, file, and parentage. The file field contains the file specification for the subfunction or private function:

[fsub fprv] = get_handles;

functions(fsub)
ans = 
     function: 'mysubfun'
         type: 'scopedfunction'
         file: 'c:\matlab\get_handles.m'
    parentage: {'mysubfun'  'get_handles'}

functions(fprv)
ans = 
     function: 'myprivatefun'
         type: 'scopedfunction'
         file: 'c:\matlab\private\myprivatefun.m'
    parentage: {'myprivatefun'}

Example 3

In this example, the function get_handles_nested.m contains a nested function nestfun. This function has a single output which is a function handle to the nested function:

function handle = get_handles_nested(A)
nestfun(A);

   function y = nestfun(x)
   y = x + 1;
   end

handle = @nestfun;
end

Call this function to get the handle to the nested function. Use this handle as the input to functions to return the information shown here. Note that the function field of the return structure contains the names of the nested function and the function in which it is nested in the format. Also note that functions returns a workspace field containing the variables that are in context at the time you call this function by its handle:

fh = get_handles_nested(5);

fhinfo = functions(fh)
fhinfo = 
     function: 'get_handles_nested/nestfun'
         type: 'nested'
         file: 'c:\matlab\get_handles_nested.m'
    workspace: [1x1 struct]

fhinfo.workspace
ans = 
    handle: @get_handles_nested/nestfun
         A: 5

See Also

function_handle

function_handle (@) funm