WOLFRAM

Wolfram Language & System Documentation Center

Protected

is an attribute that prevents any values associated with a symbol from being modified.

Details
Details and Options Details and Options
Examples  
Basic Examples  
Scope  
Applications  
Properties & Relations  
See Also
Tech Notes
Related Guides
History
Cite this Page

Protected

Protected

is an attribute that prevents any values associated with a symbol from being modified.

Details

  • Many built‐in Wolfram Language functions have the attribute Protected.
  • SetOptions can be used on symbols with attribute Protected that do not also have the Locked attribute.

Examples

open all close all

Basic Examples  (2)

String has the attribute Protected:

Wolfram Language code: Attributes[String]

Set the attribute Protected on f:

Wolfram Language code: f[x_] := x ^ 2; Protect[f];
Wolfram Language code: Attributes[f]

Scope  (1)

Simultaneously protect and read protect the function f:

Wolfram Language code: f[x_] := 2x + 1; SetAttributes[f, {Protected, ReadProtected}]

f has both attributes:

Wolfram Language code: Attributes[f]

Simultaneously clear both attributes:

Wolfram Language code: ClearAttributes[f, {Protected, ReadProtected}]

Both have been cleared:

Wolfram Language code: Attributes[f]

Applications  (1)

Unprotect a system symbol to make a definition for it:

Wolfram Language code: protected = Unprotect[Sqrt]
Wolfram Language code: Sqrt[x_ ^ 2] := x

Restore protection:

Wolfram Language code: Protect[Evaluate[protected]]

Properties & Relations  (5)

Protecting a symbol is equivalent to setting the Protected attribute:

Wolfram Language code: Protect[f]; SetAttributes[g, Protected];
Wolfram Language code: Attributes[{f, g}]

Unprotecting a symbol is equivalent to clearing the Protected attribute:

Wolfram Language code: Unprotect[f]; ClearAttributes[g, Protected];
Wolfram Language code: Attributes[{f, g}]

No more definitions can be made for a protected symbol:

Wolfram Language code: f[x_] := x ^ 3
Wolfram Language code: Protect[f];
Wolfram Language code: f[x_] := x ^ 2

Neither can definitions be cleared:

Wolfram Language code: Clear[f]

To modify definitions of a protected symbol, unprotect it first:

Wolfram Language code: f[x_] := x ^ 2; Protect[f];
Wolfram Language code: f[x_] := x ^ 3
Wolfram Language code: Unprotect[f];
Wolfram Language code: f[x_] := x ^ 3

SetOptions can be used the change the default options of a protected function:

Wolfram Language code: Attributes[D]

Change the options of D:

Wolfram Language code: SetOptions[D, NonConstants -> {a, b, c}]

Restore the system default:

Wolfram Language code: SetOptions[D, NonConstants -> {}]

A symbol that is locked and protected can no longer be changed:

Wolfram Language code: Options[f] = {opt -> val}; f[x_] := x ^ 2; SetAttributes[f, {Locked, Protected}]
Wolfram Language code: f[x_] := x ^ 3
Wolfram Language code: Unprotect[f];
Wolfram Language code: SetOptions[f, opt -> newVal]
Wolfram Research (1988), Protected, Wolfram Language function, https://reference.wolfram.com/language/ref/Protected.html.

Text

Wolfram Research (1988), Protected, Wolfram Language function, https://reference.wolfram.com/language/ref/Protected.html.

CMS

Wolfram Language. 1988. "Protected." Wolfram Language & System Documentation Center. Wolfram Research. https://reference.wolfram.com/language/ref/Protected.html.

APA

Wolfram Language. (1988). Protected. Wolfram Language & System Documentation Center. Retrieved from https://reference.wolfram.com/language/ref/Protected.html

BibTeX

@misc{reference.wolfram_2026_protected, author="Wolfram Research", title="{Protected}", year="1988", howpublished="\url{https://reference.wolfram.com/language/ref/Protected.html}", note=[Accessed: 12-June-2026]}

BibLaTeX

@online{reference.wolfram_2026_protected, organization={Wolfram Research}, title={Protected}, year={1988}, url={https://reference.wolfram.com/language/ref/Protected.html}, note=[Accessed: 12-June-2026]}