ReflectionParameter

:::info[Note] This is a point-in-time snapshot of the API documentation from January 2026. Going forward, we will not be maintaining a public copy of these references, and recommend users to refer to the built-in signature helpers available in the Hack LSP instead for complete and up-to-date information. :::

( excerpt from http://php.net/manual/en/class.reflectionparameter.php )

The ReflectionParameter class retrieves information about function's or method's parameters.

To introspect function parameters, first create an instance of the ReflectionFunction or ReflectionMethod classes and then use their ReflectionFunctionAbstract::getParameters() method to retrieve an array of parameters.

Interface Synopsis

class ReflectionParameter implements Reflector {...}

Public Methods

• ::export($function, $parameter, $return = false)
  ( excerpt from http://php.net/manual/en/reflectionparameter.export.php )
• ->__construct($function, $parameter, $info = NULL)
  ( excerpt from http://php.net/manual/en/reflectionparameter.construct.php )
• ->__toString()
• ->allowsNull()
  ( excerpt from http://php.net/manual/en/reflectionparameter.allowsnull.php )
• ->canBePassedByValue()
  ( excerpt from http://php.net/manual/en/reflectionparameter.canbepassedbyvalue.php )
• ->getAttribute(string $name): ?varray<mixed>
• ->getAttributeClass<T as HH\ParameterAttribute>(classname<T> $c): ?T
• ->getAttributes(): darray<string, varray<mixed>>
• ->getAttributesNamespaced()
• ->getClass()
  ( excerpt from http://php.net/manual/en/reflectionparameter.getclass.php )
• ->getDeclaringClass()
  ( excerpt from http://php.net/manual/en/reflectionparameter.getdeclaringclass.php )
• ->getDeclaringFunction()
  ( excerpt from http://php.net/manual/en/reflectionparameter.getdeclaringfunction.php )
• ->getDefaultValue()
  ( excerpt from http://php.net/manual/en/reflectionparameter.getdefaultvalue.php )
• ->getDefaultValueConstantName()
  ( excerpt from php.net/manual/en/reflectionparameter.getdefaultvalueconstantname.php )
• ->getDefaultValueText()
  This is an HHVM only function that gets the raw text associated with a default parameter
• ->getName()
  ( excerpt from http://php.net/manual/en/reflectionparameter.getname.php )
• ->getPosition()
  ( excerpt from http://php.net/manual/en/reflectionparameter.getposition.php )
• ->getType(): ?ReflectionType
  ( excerpt from http://php.net/manual/en/reflectionparameter.gettype.php )
• ->getTypeText(): string
• ->getTypehintText()
• ->hasAttribute(string $name): bool
• ->hasType(): bool
  ( excerpt from http://php.net/manual/en/reflectionparameter.hastype.php )
• ->isArray()
  ( excerpt from http://php.net/manual/en/reflectionparameter.isarray.php )
• ->isCallable()
  ( excerpt from http://php.net/manual/en/reflectionparameter.iscallable.php )
• ->isDefaultValueAvailable()
  ( excerpt from http://php.net/manual/en/reflectionparameter.isdefaultvalueavailable.php )
• ->isDefaultValueConstant(): ?bool
  ( excerpt from http://php.net/manual/en/reflectionparameter.isdefaultvalueconstant.php )
• ->isInOut(): bool
  Checks if this is an inout parameter
• ->isOptional(): bool
  ( excerpt from http://php.net/manual/en/reflectionparameter.isoptional.php )
• ->isPassedByReference()
  ( excerpt from http://php.net/manual/en/reflectionparameter.ispassedbyreference.php )
• ->isReadonly(): bool
  Checks if this is a readonly parameter
• ->isVariadic(): bool
  Checks if the parameter is variadic
• ->toString()
  ( excerpt from http://php.net/manual/en/reflectionparameter.tostring.php )