---
name: "isbddvarinsupport"
section: "3"
platform: "linux"
package: "alliance"
version: "5.1.1-3"
release: "Debian 10 (Buster)"
platforms: ["linux"]
url: "https://new.carta.tech/isbddvarinsupport"
---

# isbddvarinsupport(3)

tests if a variable appears in a bdd.

## NAME

isbddvarinsupport - tests if a variable appears in a **bdd**.

## SYNOPSYS

```
#include "bdd101.h"
int isbddvarinsupport( BddSystem, BddNode, Variable )
  bddsystem ∗BddSystem;
  bddnode   ∗BddNode;
  bddvar     Variable;
```

## PARAMETERS

- *BddSystem*

  The **bdd** system.

- *BddNode*

  The **bdd** node.

- *Variable*

  The variable number.

## DESCRIPTION

**isbddvarinsupport** tests if the variable number *Variable* appears in the support of the **bdd** node *BddNode*, in the **bdd** system *BddSystem*. If a null pointer is given, the default **bdd** system is used.\

## RETURN VALUE

**isbddvarinsupport** returns 1 if *Variable* appears, 0 otherwise.

## ERRORS

**"variable xxx out of range, error !"**

The *Variable* parameter must be less or equal to the *BddSystem-\>NUMBER\_VAR* field.

## EXAMPLE

```
#include "bdd101.h"
   bddsystem  ∗BddSystem;
   bddcircuit ∗BddCircuit;
   bddnode    ∗BddNode;
   bddnode    ∗BddVariable;
   chain_list ∗Expr;
   bddvar         Variable;
   BddSystem  = createbddsystem( 100, 1000, 100, 50000 );
   BddCircuit = createbddcircuit( "hello_world", 10, 10, BddSystem );
   Expr = createablbinexpr( ABL_AND,
                            createablatom( "i0" ),
                            createablatom( "i1" ) );
   BddNode = addbddcircuitabl( BddCircuit, Expr );
   freeablexpr( Expr );
   BddVariable = searchbddcircuitin( (bddcircuit ∗)0, "i0" );
   Variable = getbddvarbyindex( (bddsystem ∗ 0), BddVariable->INDEX ) );
   /* displays 1 */
   printf( "%d", isbddvarinsupport( (bddsystem ∗)0, BddNode, Variable ) );
   destroybddsystem( (bddsystem ∗)0 );
   destroybddcircuit( (bddcircuit ∗)0 );
```

## SEE ALSO

[**bdd**(1)](/bdd/1.md)