# VHDL233: Synthesizable functions and procedures should not use external signals and variables ## Summary ```{raw} html

Count: 1

ReliabilitySecurityMaintainabilityCode attributeEffort to fixTags
HIGH--Intentionality | Logical30minsynthesis, do254, vscode, linter, do254-cp9
``` ## Description ```{raw} html

Noncompliant code example

architecture a of e is
  signal s : std_logic;

  pure function f1 return type1 is -- Noncompliant: Mark this function as "impure" instead or remove the usage of the "s" signal
  begin
    s <= '0';
    return sig;
  end;

  function f2 return type1 is -- Noncompliant: Mark this function as "impure" or remove the usage of the "s" signal
  begin
    s <= '0';
    return sig;
  end;

begin
end;

Compliant solution

architecture a of e is
  signal s : std_logic;

  impure function f3 return type1 is -- Compliant
  begin
    s <= '0';
    return sig;
  end;

begin
end;

Synthesizable functions and procedures should not use external signals and variables.

``` ## Parameters No parameters. ```{raw} html ```